123975-95-1Relevant articles and documents
Highly Enantiospecific Synthesis of 4-Alkyl and 4,5-Dialkyl Substituted 4,5-Dihydrofuran-2(3H)-ones from Optically Active (E)- and (Z)-Alk-1-enyl p-Tolyl Sulphoxides: Application to the Synthesis of Lignan Lactones
Kosugi, Hiroshi,Tagami, Katsuya,Takahashi, Akira,Kanna, Hiroshi,Uda, Hisashi
, p. 935 - 943 (2007/10/02)
Stereochemically and optically pure 2-substituted ethylenic p-tolyl sulphoxides (R)-E-(4) and (R)-Z-(4) undergo readily and stereospecifically an additive Pummerer rearrangement reaction with dichloroketene to give trans- and cis-β-alkyl-α,α-dichloro-γ-p-tolylthio-γ-butyrolactone derivatives (5), respectively.Sequential reductive dechlorination and desulphurization lead to (-)-(S)-, from trans-(5), and (+)-(R)-β-alkyl-γ-butirolactones (7), from cis-(5), with a high optical purity, respectively.Reaction of the intermediate tolylthio derivatives (6) with allyltributylstannane gives β-alkyl-γ-allyl-γ-butyrolactones (15) and (16).These sequential reactions can be successfully applied to the synthesis of (+)-(R)-β-piperonylbutyrolactone (20), the key intermediate for the synthesis of antileukemic lignan lactones, in high chemical and optical yields.Acylation of compound (20) with 3,4,5-trimethoxybenzoyl chloride furnishes (+)-podorhizon (21).
