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shapiro reaction wikipedia jump to content main menu main menu move to sidebar hide navigation main page contents current events random article about wikipedia contact us contribute help learn to edit community portal recent changes upload file special pages search search appearance donate create account log in personal tools donate create account log in contents move to sidebar hide top 1 reaction mechanism and directionality 2 scope 3 catalytic shapiro reaction 4 a one pot in situ combined shapiro suzuki reaction 5 an application of the shapiro reaction in total synthesis 6 see also 7 references toggle the table of contents shapiro reaction 8 languages čeština deutsch español فارسی suomi 日本語 српски srpski 中文 edit links article talk english read edit view history tools tools move to sidebar hide actions read edit view history general what links here related changes upload file permanent link page information cite this page get shortened url switch to legacy parser print export download as pdf printable version in other projects wikimedia commons wikidata item appearance move to sidebar hide from wikipedia the free encyclopedia organic reaction shapiro reaction named after robert h shapiro reaction type coupling reaction identifiers organic chemistry portal shapiro reaction rsc ontology id rxno 0000125 the shapiro reaction or tosylhydrazone decomposition is an organic reaction in which a ketone or aldehyde is converted to an alkene through an intermediate hydrazone in the presence of 2 equivalents of organolithium reagent 1 2 3 the reaction was discovered by robert h shapiro in 1967 4 the shapiro reaction was used in the nicolaou taxol total synthesis 5 this reaction is very similar to the bamford stevens reaction which also involves the basic decomposition of tosyl hydrazones the shapiro reaction reaction mechanism and directionality edit in a prelude to the actual shapiro reaction a ketone or an aldehyde is converted to the tosylhydrazone two equivalents of n butyllithium gives the carbanion which produces a carbon carbon double bond ejecting the tosyl anion the resulting diazonium anion loses molecular nitrogen giving the vinyllithium species the reaction s directionality is controlled by the stereochemistry of the hydrazone with deprotonation occurring cis to the tosylamide group this is due to coordination by the nitrogen atom 6 intermediate explaining directionality of the shapiro reaction scope edit the position of the alkene in the product is controlled by the site of deprotonation by the organolithium base in general the kinetically favored less substituted site of differentially substituted tosylhydrazones is deprotonated selectively leading to the less substituted vinyllithium intermediate although many secondary reactions exist for the vinyllithium functional group in the shapiro reaction in particular water is added resulting in protonation to the alkene 7 other reactions of vinyllithium compounds include alkylation reactions with for instance alkyl halides 8 shapiro reactions starting from camphor 1 through the intermediate hydrazone 2 to the vinyllithium 3 addition of water c results in 2 bornene 4 and addition of an alkyl bromide d gives 5 importantly the shapiro reaction cannot be used to synthesize 1 lithioalkenes and the resulting functionalized derivatives as sulfonylhydrazones derived from aldehydes undergo exclusive addition of the organolithium base to the carbon of the c n double bond 9 catalytic shapiro reaction edit traditional shapiro reactions require stoichiometric sometimes excess amounts of base to generate the alkenyllithium reagents to combat this problem yamamoto and coworkers developed an efficient stereoselective and regioselective route to alkenes using a combination of ketone phenylaziridinylhydrazones as arenesulfonylhydrazone equivalents with a catalytic amount of lithium amides the required phenylaziridinylhydrazone was prepared from the condensation of undecan 6 one with 1 amino 2 phenylaziridine treatment of the phenylaziridinylhydrazone with 0 3 equivalents of lda in ether resulted in the alkene shown below with a cis trans ratio of 99 4 0 6 the ratio was determined by capillary glc analysis after conversion to the corresponding epoxides with mcpba the catalyst loading can be reduced to 0 05 equivalents in the case of a 30mmol scale reaction the high stereoselectivity is obtained by the preferential abstraction of the α methylene hydrogen syn to the phenylaziridine and is also accounted for by the internal chelation of the lithiated intermediated 10 the shapiro reaction with n aziridinylhydrazones produces the alkene product as well as stryrene and gaseous nitrogen as byproducts the cycle of the catalytic shapiro reaction is also shown a one pot in situ combined shapiro suzuki reaction edit the shapiro reaction can also be combined with the suzuki reaction to produce a variety of olefin products keay and coworkers have developed methodology that combines these reactions in a one pot process that does not require the isolation of the boronic acid a setback of the traditional suzuki coupling this reaction has a wide scope tolerating a slew of trisylhydrazones and aryl halides as well as several solvents and pd sources 11 the shapiro and suzuki reactions are combined to yield a variety of alkene products an application of the shapiro reaction in total synthesis edit the shapiro reaction has been used to generate olefins towards to complex natural products k mori and coworkers wanted to determine the absolute configuration of the phytocassane group of a class of natural products called phytoalexins this was accomplished by preparing the naturally occurring phytocassane d from r wieland miescher ketone on the way to phytocassane d a tricyclic ketone was subjected to shapiro reaction conditions to yield the cyclic alkene product 12 use of the shapiro reaction in the synthesis of phytocassane d see also edit hydrazone iodination wolff kishner reduction references edit shapiro r h lipton m f kolonko k j buswell r l capuano l a 1975 tosylhydrazones and alkyllithium reagents more on the regiospecificity of the reaction and the trapping of three intermediates tetrahedron lett 16 22 23 1811 1814 doi 10 1016 s0040 4039 00 75263 4 shapiro robert h 1976 alkenes from tosylhydrazones org react 23 3 405 507 doi 10 1002 0471264180 or023 03 isbn 978 0471264187 cite journal cs1 maint periodical has isbn link adlington robert m barret anthony g m 1983 recent applications of the shapiro reaction acc chem res 16 2 55 59 doi 10 1021 ar00086a004 shapiro robert h heath marsha j 1967 tosylhydrazones v reaction of tosylhydrazones with alkyllithium reagents a new olefin synthesis j am chem soc 89 22 5734 5735 bibcode 1967jachs 89 5734s doi 10 1021 ja00998a601 nicolaou kyriacos c sorensen erik j 1996 classics in total synthesis targets strategies methods wiley isbn 9783527292318 吕 萍 2022 中级有机化学 反应与机理 intermediate organic chemistry reactions and mechanisms in chinese 2nd ed 高等教育出版社 pp 279 280 isbn 978 7 04 058063 1 shapiro r h duncan j h 1971 2 bornene 1 7 7 trimethylbicyclo 2 2 1 hept 2 ene organic syntheses 51 66 doi 10 15227 orgsyn 051 0066 collected volumes vol 6 chamberlin a richard liotta ellen l bond f thomas 1983 generation and reactions of alkenyllithium reagents 2 butylbornene organic syntheses 61 141 doi 10 15227 orgsyn 061 0141 collected volumes vol 7 p 77 chamberlin a richard bloom steven h 1990 lithioalkenes from arenesulfonylhydrazones org react 39 1 1 83 doi 10 1002 0471264180 or039 01 maruoka keiji oishi masataka yamamoto hisashi 1991 the catalytic shapiro reaction j am chem soc 118 9 2289 2290 doi 10 1021 ja951422p passafaro marco s keay brian a 1996 a one pot in situ combined shapiro suzuki reaction tetrahedron lett 37 4 429 432 doi 10 1016 0040 4039 95 02210 4 yajima arata mori kenji 2000 synthesis and absolute configuration of phytocassane d a diterpene phytoalexin isolated from the rice plant oryza sativa eur j org chem 2000 24 4079 4091 doi 10 1002 1099 0690 200012 2000 24 4079 aid ejoc4079 3 0 co 2 r v t e alkenes alkenes ethene c 2 h 4 propene c 3 h 6 butene c 4 h 8 pentene c 5 h 10 hexene c 6 h 12 heptene c 7 h 14 octene c 8 h 16 nonene c 9 h 18 decene c 10 h 20 polyenes preparations dehydrohalogenation from haloalkane dehydration reaction from alcohol semihydrogenation from alkyne bamford stevens reaction barton kellogg reaction boord olefin synthesis chugaev elimination cope reaction corey winter olefin synthesis grieco elimination hofmann elimination horner wadsworth emmons reaction hydrazone iodination julia olefination kauffmann olefination mcmurry reaction peterson olefination ramberg bäcklund reaction shapiro reaction takai olefination wittig reaction olefin metathesis ene reaction cope rearrangement reactions hydrogenation halogenation hydration electrophilic addition oxymercuration reaction hydroboration cyclopropanation epoxidation dihydroxylation ozonolysis hydrohalogenation polymerization diels alder reaction wacker process dehydrogenation ene reaction friedel crafts alkylation retrieved from https en wikipedia org w index php title shapiro_reaction oldid 1297322286 categories carbon carbon bond forming reactions olefination reactions organic redox reactions name reactions hidden categories articles with short description short description matches wikidata cs1 maint periodical has isbn cs1 chinese language sources zh this page was last edited on 25 june 2025 at 13 11 utc page was rendered with parsoid text is available under the creative commons attribution sharealike 4 0 license additional terms may apply by using this site you agree to the terms of use and privacy policy wikipedia is a registered trademark of the wikimedia foundation inc a non profit organization privacy policy about wikipedia disclaimers contact wikipedia legal safety contacts code of conduct developers statistics cookie statement mobile view search search toggle the 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