Comprehensive Organic Functional Group Transformations, Volume 6 (Synthesis: Carbon with Three or Four Attached Heteroatoms)

836 Pages·2003·10.86 MB·English

by  Alan R. Katritzky

Comprehensive Organic Functional
Group Transformations, Volume 6
Elsevier, 2003

Editors-in-Chief: Alan R. Katritzky, Otho Meth-Cohn, and Charles W. Rees

Synthesis: Carbon with Three or Four Attached
Heteroatoms

Part I: Tetracoordinated Carbon with Three Attached Heteroatoms, RCXX′X″

6.01 Trihalides, Pages 1-33, Richard D. Chambers and John Hutchinson

6.02 Functions Containing Halogens and Any Other Elements,
Pages 35-66, Graham B. Jones and Jude E. Matthews
6.03 Functions Containing Three Chalcogens (and No Halogens),
Pages 67-102, Glynn Mitchell
6.04 Functions Containing a Chalcogen and Any Other Heteroatoms
Other Than a Halogen, Pages 103-136, Martin J. Rice
6.05 Functions Containing at Least One Group 15 Element
(and No Halogen or Chalcogen), Pages 137-170, David P. J. Pearson
6.06 Functions Containing at Least One Metalloid (Si, Ge, or B) and No
Halogen, Chalcogen or Group 15 Element; Also Functions Containing
Three Metals, Pages 171-210, Vadim D. Romanenko, Michel Sanchez
and Jean-Marc Sotiropoulos

Part II: Tetracoordinated Carbon with Four Attached Heteroatoms,
CXX′X″X‴

6.07 Functions Containing Four Halogens or Three Halogens and One
Other Heteroatom Substituent, Pages 211-247, Alex H. Gouliaev
and Alexander Senning
6.08 Functions Containing Two Halogens and Two Other Heteroatom
Substituents, Pages 249-270, Anastassios Varvoglis
by kmno4
6.09 Functions Containing One Halogen and Three Other Heteroatom
Substituents, Pages 271-293, Angela Marinetti and Philippe Savignac
6.10 Functions Containing Four or Three Chalcogens (and No Halogens),
Pages 295-318, Alex H. Gouliaev and Alexander Senning
6.11 Functions Containing Two or One Chalcogens (and No Halogens),
Pages 319-358, Wolfgang Petz and Frank Weller
6.12 Functions Containing at Least One Group 15 Element
(and No Halogen or Chalcogen), Pages 359-375, Duncan Carmichael,
Angela Marinetti and Philippe Savignac
6.13 Functions Containing at Least One Metalloid (Si, Ge or B) and No
Halogen, Chalcogen or Group 15 Element; Also Functions Containing
Four Metals, Pages 377-406, Paul D. Lickiss

Part III: Tricoordinated Carbon with Three Attached Heteroatoms, Y=CXX′

6.14 Functions Containing a Carbonyl Group and at Least One Halogen,
Pages 407-457, Geoffrey E. Gymer and Subramaniyan Narayanaswami
6.15 Functions Containing a Carbonyl Group and at Least One Chalcogen
(but No Halogen), Pages 459-498, Heiner Eckert and Alfons Nestl
6.16 Functions Containing a Carbonyl Group and Two Heteroatoms Other
Than a Halogen or Chalcogen, Pages 499-526, Anthony F. Hegarty and
Leo J. Drennan
6.17 Functions Containing a Thiocarbonyl Group and at Least One
Halogen; Also at Least One Chalcogen and No Halogen,
Pages 527-567, Erich Kleinpeter and Kalevi Pihlaja
6.18 Functions Containing a Thiocarbonyl Group Bearing Two
Heteroatoms Other Than a Halogen or Chalcogen, Pages 569-585,
José Barluenga, Eduardo Rubio and Miguel Tomás
6.19 Functions Containing a Selenocarbonyl or Tellurocarbonyl
Group—SeC(X)X′ and TeC(X)X′, Pages 587-599, Frank S. Guziec
and Lynn J. Guziec
6.20 Functions Containing an Iminocarbonyl Group and at Least One
Halogen; Also One Chalcogen and No Halogen, Pages 601-637,
Thomas L. Gilchrist
6.21 Functions Containing an Iminocarbonyl Group and Any Elements
Other Than a Halogen or Chalcogen, Pages 639-675, Ian A. Cliffe
6.22 Functions Containing Doubly Bonded P, As, Sb, Bi, Si, Ge, B or
a Metal, Pages 677-724, Vadim D. Romanenko, Michel Sanchez and
Lydia Lamandé

Part IV: Tricoordinated Stabilized Cations and Radicals, +CXYZ and ·CXYZ

6.23 Tricoordinated Stabilized Cations and Radicals, +CXYZ and ·CXYZ,
Pages 725-734, Thomas L. Gilchrist
6.24 References to Volume 6, Pages 735-844
by kmno4
6.01
Trihalides
RICHARD D. CHAMBERS
UniversityofDurham,UK
and
JOHN HUTCHINSON
BNFLFluorochemicalsLtd.,Durham,UK
5[90[0 GENERALMETHODS 0
5[90[0[0 TheAdditionofHalo‘ensandInterhalo‘enCompoundstoFluoroalkenes 1
5[90[0[1 TheAdditionofHaloalkanestoHaloalkenes 3
5[90[0[1[0 Lewisacid!catalysedadditionoftrihalomethylcationstohaloalkenes*thePrinsreaction 3
5[90[0[1[1 Additionsinitiatedbyfreeradicals\heatorradiation 3
5[90[0[1[2 Additionscatalysedbysaltsandcomplexesoftransitionmetals 5
5[90[0[1[3 Additionsinducedelectrochemically 6
5[90[0[2 ThePreparationofC Chloro~uorohydrocarbons 6
1
5[90[1 TRIFLUOROMETHYLDERIVATIVES*RCF 8
2
5[90[1[0 General 8
5[90[1[1 ArylDerivatives 8
5[90[1[1[0 Conversionof‘roupsattachedtoanaromaticrin‘intothetri~uoromethyl‘roup 8
5[90[1[1[1 Substitutionbytri~uoromethylradicals 00
5[90[1[1[2 Substitutionofhydro‘enbythetri~uoromethyl‘roupactin‘asanelectrophile 01
5[90[1[1[3 Substitutionofhalo‘ensbythetri~uoromethyl‘roupactin‘asanucleophile 02
5[90[1[1[4 Substitutionofhalo‘ensbythetri~uoromethyl‘roupusin‘derivativesofmetals 03
5[90[1[2 DerivativesofAlkanes\Alkenes\AlkynesandOtherSaturatedCompounds 05
5[90[1[2[0 Halo‘enexchan‘e 05
5[90[1[2[1 Conversionsofother‘roupstothetri~uoromethyl‘roup 08
5[90[1[2[2 Transferoftri~uoromethyl‘roupsasradicals 19
5[90[1[2[3 Reactionsinvolvin‘tri~uoromethylderivativesofmetalsandmetalloids 11
5[90[2 TRICHLOROMETHYLDERIVATIVES*RCCl 12
2
5[90[2[0 TrichloromethylGroupsAttachedtoanAliphaticCentre 12
5[90[2[0[0 Conversionof‘roupsattachedtoanaliphaticcentreintothetrichloromethyl‘roup 12
5[90[2[0[1 Transferofthetrichloromethyl‘rouptoanaliphaticcentre 12
5[90[2[1 TrichloromethylGroupsAttachedtoanAromaticRin‘ 16
5[90[2[1[0 Conversionof‘roupsattachedtoanaromaticrin‘intothetrichloromethyl‘roup 17
5[90[2[1[1 Transferofthetrichloromethyl‘rouptoanaromaticrin‘ 18
5[90[3 TRIBROMOMETHYLDERIVATIVES*RBr 20
2
5[90[4 MIXEDSYSTEMSWITHFLUORINE*RCFHal 21
1
5[90[5 MIXEDHALOFORMS*CHXY ANDCHXYZ 21
1
5[90[0 GENERALMETHODS
Thereareseveralgeneralmethodswhichcanleadtotrihalomethylcompoundswherethehalogen
atomscan bethe sameordi}erent[ Itwillbe seenthat someofthese methodsleadto compounds
0
1 Trihalides
inwhichtherearetwosuchtrihalomethylgroups[Forsimplicity\thegeneralmethodsarediscussed
_rst[
5[90[0[0 TheAdditionofHalogensandInterhalogenCompoundstoFluoroalkenes
Theadditionofhalogensandinterhalogencompoundsto~uoroalkenesa}ordsavaluablemethod
forthepreparationofcompoundscontainingthegroup0CHal wherethehalogenatomsmaybethe
2
sameordi}erent[Theadditionofhalogensisconvenientlycarriedoutunderultravioletirradiation
"Equations"0#and"1##(cid:2)30JA2365\57JOC0905(cid:3)\buttheadditionofiodinetotetra~uoroetheneoccurs
onlyatelevatedtemperatures"Equation"2##(cid:2)38JCS1837\38JOC636\42JCS0437\52USP2965930(cid:3)[Generally
the yields of the adducts are high\ but when 0\0!di~uoroethene is treated with iodine a mixture of
compoundsisobtained\themostabundantofwhichisCF CH I"Equation"3##(cid:2)47JOC211(cid:3)[
2 1
F3C Cl Cl2, UV F3C Cl
F Cl (1)
F Cl Cl Cl
OH OH
RF F Br2, UV RF F
(2)
F F
F F Br Br
F F F F
i, ii or iii
F F (3)
F F I I
i, I, EtO, 60 °C, 15 h; ii, I, 150 °C, 24 h; iii, I, KI, HO, 100 °C, 5 h
2 2 2 2 2
F F I I F F I
I2, 185 °C, 16 h F + F + F + (4)
F F F F F
The addition of the interhalogen compounds ICl and IBr to ~uoroalkenes also can be used to
givecompoundshavingthegroup0CHal [Withasymmetricalkenes\theadditionisregioselective\
2
buttheprecisecompositionoftheproductisin~uencedbythereactionconditionsandthepresence
ofcatalysts[ThereactionsshowninEquations"4#(cid:1)"8#werecarriedoutbyseveralworkersandthus
under di}erent sets of conditions (cid:2)41JCS3312\43JCS812\50JCS2668\50JA1384\51JOC0371\53JOC141(cid:3)^ the
yieldsand\wheremorethanoneisomerwasobtained\isomerratioswerecorrespondinglydi}erent[
F F F F F F
+ ICl I Cl + Cl I (5)
F Cl F Cl F Cl
F F F F F F
+ ICl I + Cl (6)
F F Cl F I
F Cl F Cl F Cl
+ ICl I Cl + Cl I (7)
F Cl F Cl F Cl
F F F F F F
+ IBr I Br + Br I (8)
F Cl F Cl F Cl
F F I
+ IBr Br (9)
F F
The elements bromine and ~uorine\ or iodine and ~uorine\ can be added to ~uoroalkenes by
treatingthealkenewithamixtureofbrominetri~uorideandbromine\oriodinepenta~uorideand
iodine "Equations "09#(cid:1)"11##[ Here\ {IF| refers to a stoichiometric mixture of iodine penta~uoride
GeneralMethods 2
and iodine "IF (cid:27)1I 04{IF|#\ and {BrF| to a stoichiometric mixture of bromine tri~uoride and
4 1
bromine"BrF (cid:27)Br 02{BrF|#[Whiletheadditionof{BrF|to~uoroalkenesisvigorousandneeds
2 1
to be moderated\ the corresponding reactions of {IF| are carried out at elevated temperatures
(cid:2)50JCS2668(cid:3)\ and catalysts may be added (cid:2)50JA1272\ 73JAP4840114(cid:3)[ The addition of {IF| to tetra!
~uoroethene is particularly important because the product\ penta~uoroiodoethane\ is a starting
materialinone ofthecommercialroutesto~uorochemical surfactantsandsurfacetreatments(cid:2)B!
68MI 590!90(cid:3)[ Additions to hexa~uoropropene and 0\0!di~uoroethene give single isomers\ but
additionstochlorotri~uoroetheneand0\0!dichlorodi~uoroetheneyieldmixturesofisomerswhose
composition is related to the reaction conditions[ The reaction of {IF| to tetrachloroethene results
in ~uorination only "Equation "07##[ For the addition of {IF| to internal alkenes with the formula
CF "CF # CF1C"CF # \specialproceduresarenecessary"Equation"11##[Eitherpotassium~uoride
2 1 n 2 1
must be added to the {IF| mixture\ or the alkene may _rst be treated with AgF or AgF:KF in a
polaraproticsolventtomakethesilversalt\whichinturnistreatedwithiodinetogivethedesired
product (cid:2)76JFC"26#112(cid:3)[ These products are tertiary per~uoroiodoalkanes and are highly toxic\ so
specialcaremustbetakenduringtheirpreparation[
F F F F
+ 'IF' F I (10)
F F F F
F3C F F3C F
+ 'IF' I F (11)
F F F F
F F F F F F
+ 'IF' F I + I F (12)
F Cl F Cl F Cl
F Cl F Cl F Cl
+ 'IF' F I + I F (13)
F Cl F Cl F Cl
F F F F
+ 'IF' I F (14)
Cl Cl Cl Cl
F Cl F Cl
+ 'IF' F (15)
F F I
F F F F
+ 'IF' F (16)
F F I
F F I
+ 'IF' F (17)
F F
Cl Cl Cl Cl
+ 'IF' Cl Cl (18)
Cl Cl F F
F F F F
+ 'BrF' F F (19)
F F F Br
F3C F F3C F
+ 'BrF' F F (20)
F F Br F
3 Trihalides
F F F F F F
+ 'BrF' Br F + F Br (21)
F Cl F Cl F Cl
CF3(CF2)n CF3 CF3(CF2)n CF3
+ 'IF' F CF3 (22)
F CF F I
3
5[90[0[1 TheAdditionofHaloalkanestoHaloalkenes
The addition of haloalkanes to haloalkenes can be used to generate alkanes which bear a tri!
halomethyl group "Equation "12##[ If the alkene is perhalogenated\ then it can be seen that the
adduct will have twotrihalomethyl groups[ These addition reactions can beinitiated in four main
ways\thatis\byLewisacids\byfreeradicalinitiators\bysaltsandcomplexesofcertaintransition
metals\andelectrochemically[
RX + R X (23)
5[90[0[1[0 Lewisacid!catalysedadditionoftrihalomethylcationstohaloalkenes*thePrinsreaction
The aluminum chloride!catalysed addition of chloroalkanes to chloroalkenes has been known
sincethebeginningofthiscentury\andisknownasthePrinsreaction(cid:2)03JPR304\24RTC138\24RTC296(cid:3)[
More recently\ the reaction has been extended to include the addition of chloro~uoromethanes to
~uoroalkenes and chloro~uoroalkenes[ While most of the activity in this area occurred up to the
early 0869s\ and was reviewed by Paleta (cid:2)66FCR28(cid:3) and by Paleta and Posta (cid:2)61CLY826(cid:3)\ interest
hasbeenrenewedrecentlybecausetheadductsmaybeintermediatesinthemanufactureofpotential
replacementsforthehigher!boilingchloro~uorocarbons"e[g[\(cid:2)80MIP590!90\80EUP310211\81EUP362094\
81JAP93053928(cid:3)#[Mostcommonly\thehalomethanesusedinthesereactionsareCCl \CHCl \CFCl
3 2 2
and CFHCl \ and these have been added to the alkenes CF 1CF \ CF 1CFCl\ CF 1CCl \
1 1 1 1 1 1
CFCl1CCl \ CCl 1CFCl\ C Cl \ CHCl1CHCl\ CF 1CFH\ CF 1CH and CF 1CHCl "see
1 1 1 3 1 1 1 1
Table 0#[ The addition of halomethanes to asymmetric perhalogenated ~uoroalkenes proceeds
nonregiospeci_cally\butcorrespondingadditionstothehydrogen!containingalkenesCFCl1CFH\
CF 1CFH\ CF 1CH and CF 1CHCl are highly regioselective\ with the electrophilic haloalkyl
1 1 1 1
groupbecomingattachedtothecarbonwhichbearsthehydrogen[Thissuggeststhatthepreferred
isomer is that in which most of the ~uorine atoms on the precursor alkene are attached to the
carbon where positive charge develops in the initial stages of the reaction[ In reactions with
~uorotrichloromethane\ both C0F and C0Cl bonds are cleaved\ although cleavage of the C0F
bond is preferred due to the greater Al0F bond strength[ In its reaction with the alkenes
CFCl1CHF and CF 1CHCl the C0F bond is cleaved exclusively[ Some examples of these
1
reactionsaregiveninTable0\whereitcanbeseenhowtheapproachcanbeusedtogiveavariety
of propanes with various trihalomethyl groups attached to carbon atoms[ It is probable that the
primaryproductsineachofthesereactionsundergorearrangementorfurtherreaction\andtherefore
thecompositionandnatureoftheobservedproductsaredependentuponreactionconditions[
5[90[0[1[1 Additionsinitiatedbyfreeradicals\heatorradiation
When subjected to heat\ light\ or free radical initiators such as peroxides or azo compounds\
haloalkanesaddtoalkenesandhaloalkenes"Scheme0#[
Whetherasimpleadductoramixtureofhighmolecular!weighttelomersisobtainedisdetermined
bytherelativeratesofthepropagation\transferandterminationreactions[Thus\compoundswith
theweakestC0Xbond\thatis\iodides\givelowermolecular!weightproducts\asdoalkeneswhich
aredi.culttopolymerizeundertheconditionsofthereaction[Butifthealkeneiseasilypolymerized\
for example tetra~uoroethene\ or if the telogen is not particularly reactive\ high molecular!weight
GeneralMethods 4
Table0 Lewisacid!catalysedadditionofhaloalkanestohaloalkenes[
*(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
Yield Composition
Reactants Conditions ")# Products ")# Ref[
*(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
CFCl CFCF (cid:21)14>C:2h 69 CFCFCCl\CFClCFCFCl 72\06 60CCC0756
2 1 1 2 1 2 1 1 1
CHFCl CFCF 04>C:2[4h 47 CFCFCHCl\CFClCFCHFCl 48\30 60CCC0756
1 1 1 2 1 1 1 1
CFCl CFCCl 11>C:06h 31 CFCClCCl\CFClCFCCl\ 34\37\6 55CCC2473
2 1 1 2 1 2 1 1 2
CFClCClCFCl
1 1 1
CHFCl CFCCl 6>C:01h 67 CFClCFCHCl\ 70\08 56CCC2777
1 1 1 1 1 1
CFCClCHCl\
2 1 1
CClCFCHFCl\
2 1
CFClCClCHFCl\
1 1
CFClCFClCHCl
1 1
CFCl CFCHF 9(cid:1)03>C:6h 54 CFCHFCCl\CFClCHFCFCl 69\29 63CCC0229
2 1 2 2 1 1
CHFCl CFCHF 9>C:6h 72 CFCHFCHCl\ 47\31 63CCC0229
1 1 2 1
CFClCHFCHFCl
1
*(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)
Initiation
RX R• + X•
or In2 2 In•
In• + RX R• + InX
Propagation •
R• + n R
n
Transfer
•
R + RX R X + R•
n n
Termination
• •
R + R R R
n n 2n
X• + X• X
2
•
R + X• R X
n n
Scheme 1
materialisobtained[Witheasilypolymerizedalkenes\thetelomerizationcanbecontrolledbyusing
a large excess of the telogen "preferably an iodide or diiodide# and recycling the lower telomers[
This addition of a haloalkane is often regioselective\ and it is observed that the incoming radical
generally attacks the least sterically hindered carbon[ However\ there is still debate on the factors
whichcontroltheproductsofthesereactionsandtherelativestabilityofthepotentialintermediate
radicals\andpolare}ects"notethattrihalomethylradicalsareelectrophilic#aswellassterice}ects
allplaytheirpart[
This approach is used in the manufacture of C or C per~uoroalkyl iodides\ which are inter!
7 8
mediatesinthepreparationofper~uorocarbonsurfactantsandsurfacetreatments(cid:2)B!68MI590!90(cid:3)[
Illustrative examples of these addition reactions are given in Equations "13#(cid:1)"24# "NB[ Higher
telomers are also produced in these reactions# (cid:2)36JA0099\ 89JFC"36#150\ 49JA1102\ 42JOC217\ 42JCS811\
42JCS2650\41JCS2389\53JOC0087\47JA740\76IZV797\44JA657\74T3492(cid:3) "references refer to the respective
Equations "13#(cid:1)"24##\ but many more are recorded elsewhere (cid:2)52OR"02#80\B!63MI590!90\B!65MI590!
90(cid:3)[ It is noteworthy that\ unlike other polyhaloalkanes\ trichloromethane adds to alkenes by
hydrogentransfer"Equation"15##[
5 Trihalides
Cl R
CCl + R Cl (24)
4
Cl Cl
F F Cl F
Cl Cl
CCl + (25)
4 Cl R
F R F
F F F
Cl
CClH + n-C6H13 Cl (26)
3
Cl n-CH
6 13
Cl Br
CClBr + Ph Cl (27)
3
Cl Ph
Cl I
F Cl
CCl3I + F Cl F (28)
F F
F
F F F F
F I
CFI + (29)
3 F F
F F
F F
F I
CFI + CN F (30)
3
F CN
Br Br
CFBr + OEt F (31)
2 2
F OEt
F F F
Br F Br
CFBr + F F F (32)
2 2 F
F F F
F F F
Br Br
F F Br
CBr4 + F Br F (33)
F
F
F Cl Br
CF2BrCl + F F (34)
F F F
EtOC COEt
2 2
CClBr + EtO2C CO2Et (35)
3
Br Cl
Cl Cl
5[90[0[1[2 Additionscatalysedbysaltsandcomplexesoftransitionmetals
In0845(cid:2)45CI"M#260(cid:3)\unexpectedresultswereobtainedwhenthethermaladditionsofCCl and
3
CCl Htoacrylonitrilewerecarriedoutusingasteelautoclave[Moreofthe0]0adductwasobtained
2
than expected\ and trichloromethane gave the adduct CHCl CH CHClCN rather than
1 1
GeneralMethods 6
CCl CH CH CN\ which is normally obtained in free radical additions to alkenes "vide supra#[
2 1 1
Later (cid:2)52JCS0776(cid:3)\ it was established that copper"II# and iron"III# both catalysed the addition of
tetrachloromethanetoavarietyofvinylicmonomers\andthat0]0adductswerefrequentlythesole
products\ even with easily polymerized alkenes[ This discovery led to extensive work in the area\
andcopper"II#hasnowbeenusedtocatalysetheadditionofCCl \CCl Br\CCl Br \CF CCl and
3 2 1 1 2 2
otherchlorocompoundstoalargevarietyofalkenesanddienes[Itisworthnotingthattheaddition
of CF CCl followed by hydrogenation of the adduct can be used to introduce a CF CH group[
2 2 2 1
Whilemostinvestigationsinthisareahaveusedcopper!andiron!basedcatalysts\othermetalsalts
suchassamariumdiiodide(cid:2)89JCS"P0#1920(cid:3)andvanadiumdichloride(cid:2)89SL106(cid:3)havebeenusedmore
recently[ As well as alkenes which contain only hydrogen\ halogenated alkenes and those which
containothergroupshavealsobeenused[Generallythe0]0adductistheonlyproduct\buthigher
telomers are produced when the alkene is halogenated[ However\ this method of initation always
gives lower molecular!weight material than the corresponding peroxide initiated reaction[ Amines
areoftenaddedtoformcomplexesand{increasethesolubility|ofthecopper\andconsequentlyto
increasethereactionrate[Thefollowingisnotacomprehensivelistofreferencesbutwillservetolead
the reader into the area] (cid:2)B!63MI590!90\64ACR054\65T1184\66TL3204\79CCC2377\79CCC2491\74PAC0716\
76JPS"A#2914\78JFC"34#104\89JFC"36#84\80MI590!90\81CCC0180\81JMOC40\82JFC"50#022(cid:3)[
Aswellasmetaloxides\saltsandtheircomplexeswithamines\othertransitionmetalcomplexes
such as carbonyls of iron (cid:2)56JCS"C#0049\79JOC2846(cid:3) and cobalt (cid:2)69JOC1871(cid:3)\ carbonyl complexes of
molybdenum (cid:2)71JCS"D#1170\ 89JOM"286#40(cid:3)\ iron (cid:2)89JOM"275#118(cid:3) and chromium (cid:2)73JOM"159#C64(cid:3)\
and phosphine complexes of ruthenium (cid:2)62TL4036\ 64TL788\ 67JOC0623\ 74JOM"179#286\ 76JCS"P0#0404\
81JOM40(cid:3)\rhodium(cid:2)70AG"E#364(cid:3)\rhenium(cid:2)76JCS"P0#0404(cid:3)andpalladium(cid:2)70CL0058\74T282(cid:3)haveall
been found to be e.cient catalysts in this reaction[ When the chiral Ru Cl "diop# "diop\ 1\2!O!
2 3 2
isopropylidene!1\2!dihydroxy!0\3!bis"diphenylphosphino#butane# was the catalyst\ chiral adducts
wereobtained(cid:2)76BCJ2576(cid:3)[
Clearly the metal!catalysed additions of haloalkanes to haloalkenes proceed by a di}erent
mechanismtothosepromotedbyfreeradicalinitiatorssuchasperoxides[Anymechanismneedsto
beabletoexplainthe{abnormal|additionoftrichloromethane\thesuppressionofthepropagation
step "0]0 adducts are the main products#\ and the fact that the addition of tetrachloromethane to
cyclohexeneishighlystereoselective"witharutheniumcatalyst#comparedwiththesituationwhich
obtainswhenconventionalradicalinitiatorsareused[Itisunlikelythatthedetailsofthemechanism
will be the same for all the catalysts that have been identi_ed\ but it is generally believed that it is
notasimpleredoxprocessbutoneinwhich"e[g[\forCCl #atrichloromethylradicalisformedon
3
and bound to the catalyst prior to the addition to the alkene which is itself coordinated to the
complex[
5[90[0[1[3 Additionsinducedelectrochemically
The free radical chain addition of various polyhalomethanes to alkenes has been initiated by
electrochemically in situ generated manganese salts used in a catalytic amount associated with
an equimolecular amount of a manganese"III# oxidizable compound such as methyl cyano! or
acetoacetate[Inparticular\tetrabromomethane\bromotrichloromethane\dibromodi~uoromethane
and n!heptadeca~uorooctyl iodide have been added to a variety of alkenes in high yield by this
means"Equation"25##(cid:2)81TL102(cid:3)[
X X
Mn(II) Y X
+ CXY (36)
R 3
anodic oxidation
R
CX = CBr, Y = Br; CX = CCl, Y = Br; CX = CBrF, Y = Br; CX = CF , Y = I
3 3 3 3 3 2 3 7 15
5[90[0[2 ThePreparationofC Chloro~uorohydrocarbons
1
The manufacture of saturated compounds having the general formula C H Cl F represents an
1 x y z
important part of the ~uorochemical industry[ These compounds "x(cid:30)O# "chloro~uorocarbons*
{CFC|s#havebeenusedasrefrigerants\solventsandfoam!blowingagents[However\becausethey
7 Trihalides
have been implicated in the destruction of ozone in the earth|s upper atmosphere\ they are being
replaced\underthetermsoftheMontrealProtocol\byhydro~uorocarbons"y(cid:30)O#"{HFC|s#and\
for an interim period\ by hydrochloro~uorocarbons "{HCFC|s#[ The manufacture of these
compounds is largely brought about by treating a chlorocarbon with hydrogen ~uoride and
sometimes chlorine[ Other reactions in the process may include isomerization and hydrogenation[
The ~uorinations are carried out in either the liquid phase using an antimony"V# catalyst
"Swarts| catalyst# or in the gas phase using a chromia!based catalyst[ The main routes to the C
1
chloro~uorocarbons and those compounds which are replacing them are outlined in Scheme 1[
0\0\0\1!Tetra~uoroethane"R023a#istobethemain{high!temperature|refrigerant"e[g[\mobileair
conditioning\ and domestic and industrial refrigeration# while 0\0\0!tri~uoroethane "R032a# and
0\0\0\1\1!penta~uoroethane"R014#willbeusedincompositionsfor{low!temperature|refrigeration
andstaticairconditioning"e[g[\(cid:2)82MI590!90(cid:3)#[Aswellashavingtheusesoutlinedabove\someof
thesecompoundsareintermediatesinthemanufactureofproductssuchastheanaesthetichalothane
"CF CHClBr#\andmonomerssuchas0\0!di~uoroetheneandchlorotri~uoroethene[
2
Cl Cl F Cl F F
F F
Cl F F
R133a R134a
F Cl
F
F Br
Halothane
Cl Cl F Cl F F F F
Cl F Cl Cl F Cl
Cl Cl F Cl F F F F
R113 R114 R115
F Cl F Cl F F
F F Cl F
F Cl F Cl F F
R123 R113a R125
F Cl
F F
F Cl
R114a
F F F
F F
F F
R134a R143a
Cl F F F
Cl + F + F
Cl Cl Cl F
R141b R142b R143a
Scheme 2