Acid-induced ring opening of .alpha.-bis(methylthio)methylenealkyl cyclopropyl ketones: a novel route to substituted cyclopentanones through carbocationic cyclizations
摘要:
Alpha-[Bis(methylthio)methylene]alkyl 2-styrylcyclopropyl ketones 10a-d,f and their higher enyl analogues 10e,g undergo acid-induced ring opening and carbocationic cyclizations to afford substituted cyclopentanone derivatives. The structures of these products depend on the reaction conditions and the nature of the substituent in the aryl ring. The methodology has been extended to the synthesis of 11-oxosteroid precursors 22 and 25.
Acid-induced ring opening of .alpha.-bis(methylthio)methylenealkyl cyclopropyl ketones: a novel route to substituted cyclopentanones through carbocationic cyclizations
Alpha-[Bis(methylthio)methylene]alkyl 2-styrylcyclopropyl ketones 10a-d,f and their higher enyl analogues 10e,g undergo acid-induced ring opening and carbocationic cyclizations to afford substituted cyclopentanone derivatives. The structures of these products depend on the reaction conditions and the nature of the substituent in the aryl ring. The methodology has been extended to the synthesis of 11-oxosteroid precursors 22 and 25.
Rearrangement studies on 3,3-bis(methylthio)-1-(arylcyclopropyl) -2-propen-1-ols: Synthesis of functionalized cyclopentenes and polyene esters
The cyclopropyl carbinols 8 and 9 obtained by either borohydride reduction (or Grignard addition) of the cyclopropyl ketones 1 are shown to undergo acid induced ring opening and intramolecular cyclization (5-exo or 6-endo) or deprotonation to afford either cyclopentene, biphenyl or conjugated polyene derivatives depending on the nature of Lewis acid, reaction conditions and the structuralfeatures present