Expedient Synthesis of Complex γ-Butyrolactones from 5-(1-Arylalkylidene) Meldrum’s Acids via Sequential Conjugate Alkynylation/Ag(I)-Catalyzed Lactonization
摘要:
The conjugate alkynylation of alkylidene Meldrums acids with alkynylalanes and alkynyl Grignards allows for the formation of propargylic all-carbon quaternary stereocenters in high yields. Ag2CO3-catalyzed intramolecular cyclization of propargylic Meldrums acid derivatives offers a two-step entry into complex gamma-alkylidene butyrolactones containing an all-carbon quaternary center at the C-4 position.
Expedient Synthesis of Complex γ-Butyrolactones from 5-(1-Arylalkylidene) Meldrum’s Acids via Sequential Conjugate Alkynylation/Ag(I)-Catalyzed Lactonization
作者:Siawash Ahmar、Eric Fillion
DOI:10.1021/ol502811j
日期:2014.11.7
The conjugate alkynylation of alkylidene Meldrums acids with alkynylalanes and alkynyl Grignards allows for the formation of propargylic all-carbon quaternary stereocenters in high yields. Ag2CO3-catalyzed intramolecular cyclization of propargylic Meldrums acid derivatives offers a two-step entry into complex gamma-alkylidene butyrolactones containing an all-carbon quaternary center at the C-4 position.
Asymmetric Synthesis of All-Carbon Benzylic Quaternary Stereocenters via Conjugate Addition to Alkylidene and Indenylidene Meldrum’s Acids
作者:Ashraf Wilsily、Eric Fillion
DOI:10.1021/jo901559d
日期:2009.11.20
aryl group consistently leading to high enantioselectivities. The nature of the organozinc reagent on the efficiency and selectivity of the conjugateaddition was also investigated. The solid-state conformation was determined for a number of alkylidene Meldrum’s acids and correlated with the observed enantioselectivity in relation to the arene pattern of substitution.