Phenylthio- 1-trimethylsilylethylene

Physical Data colorless liquid bp 130-134 °C/15 mmHg NMR, and MS data are available. 

Preparative Methods by lithiation of phenyl vinyl sulfide with lithium diisopropylamide, followed by silylation, or the base-induced elimination of 2-chloro-l-trimethylsilyl-l-phenylthioethane, or the lithiation of ethyl phenyl sulfoxide with LDA followed by silylation, or the Pd-catalyzed coupling reactions of trimethylstannyl phenyl sulfide with 1-bromo-1-trimethylsily lethylene.  

Cyclopentane Annulation. Condensation of l-lithio-l-(tri-methylsilyl)cyclopropane with ketones gives vinylcyclopropane intermediates, which upon pyrolysis undergo vinylcyclopropane rearrangement to give annulated cyclopentene derivatives (eq 5).  

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Phenylthiocyclobutanone, 422 Phenylthiolation, 456 Phcnylthiomethyllithium, 422-423 Phenylthiomethyl(trimethyl)silane, 423-424 1 -Phenylthio-1 -trimethylsilylethylene, 83 Phenylthio(triphenylstannyl)methyllithium, 424... 

A similar effect of a silyl substituent on Nazarov cyclizations has been reported in lit) annclation with 1-phenylthio-l-trimethylsilylethylene (equation II).3... 

Aldehydes Alkyidimesitylborane. Chloro-methyltrimethylsilane. Diethyl[(2-tetrahy-dropyranyloxy)methylphosphonate. N,N-Dimethylchloromethyleniminum chloride. Dimelhyl(methylthio)sulfonium tetrafluom-borate. Methoxy(phenylthio)methyllithium. Methylthiomethyl p-tolyl sulfone. 1-Phen-ylthio-1 -trimethylsilylethylene. Tetrakis-(Iriphcnylphosphine)palladium. Thexyl-chloroborane-Dimethyl sulfide. 

Cyclopentenone Synthesis. When activated with Lewis acid catalysts or silver ion, 1-phenylthio-l-trimethylsilylethylene reacts with a,/3-unsaturated acid chlorides at a low temperature in CH2Cl2. The cation intermediates undergo a silicon-directed Nazarov cyclization to give 3-phenylthio-substituted cyclopentenone derivatives (eq 3). The phenylthio moiety at the /3-position of cyclopentenones can be effectively utilized for the introduction of an alkyl substituent by addition/elimination. 

Analogous Reagents. 1 -Phenylsulfiny 1-1 -trimethylsilylethy-lene (1) and 1-phenylsulfonyl-l-trimethylsilylethylene (2) are used as synthetic analogs of 1-phenylthio-l-trimethylsilyl-ethylene. The sulfoxide (1) is an electron-deficient alkene so it... 

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