Catalytic, Enantioselective Vinylogous Mukaiyama Aldol Reaction of Furan-Based Dienoxy Silanes: A Chemodivergent Approach to γ-Valerolactone Flavan-3-ol Metabolites and δ-Lactone Analogues
作者:Claudio Curti、Nicoletta Brindani、Lucia Battistini、Andrea Sartori、Giorgio Pelosi、Pedro Mena、Furio Brighenti、Franca Zanardi、Daniele Del Rio
DOI:10.1002/adsc.201500705
日期:2015.12.14
a set of hydroxyphenyl γ-valerolactones was achieved starting from 2-silyloxyfuran and alkoxy-substituted benzaldehydes as common precursors. Key synthesis steps included an enantioselective vinylogous Mukaiyamaaldolreaction and a Barton–McCombie deoxygenation. Five enantioenriched γ-valerolactone targets were obtained in 5–6 steps, 18–63% overall yields and 82–98 % ee, paving the way for the straightforward
Organocatalyzed Highly Enantioselective and anti-Selective Construction of γ-Butenolides through Vinylogous Mukaiyama Aldol Reaction
作者:Ning Zhu、Bao-Chun Ma、Yong Zhang、Wei Wang
DOI:10.1002/adsc.201000099
日期:——
The formation of chiral γ‐butenolides has been achieved with good yields (up to 90%), high enantioselectivity (up to 91%) and diastereoselectivity (up to 9/1, anti‐selective) through an organocatalyzed vinylogous Mukaiyamaaldolreaction of 2‐(trimethylsilyloxy)furan and aldehydes. A wide range of chiral γ‐butenolides was obtained under mild conditions by this methodology.
The asymmetricdirect vinylogous aldolreaction of unactivated γ-butenolide with aldehydes has been developed, giving the corresponding 5-(1′-hydroxy)butenolide derivatives in high yields (up to 93%) and enantioselectivities (up to 83% ee) under mild conditions.
Denmark’s chiral bisphosphoramide/silicon tetrachloride system performs as an excellent Lewis base-Lewis acid catalyst for the vinylogous Mukaiyama aldol reaction of pyrrole- and furan-based dienoxy silanes with aromatic and heteroaromatic aldehydes. This asymmetric methodology provides a powerful synthetic entry to a variety of δ-hydroxylated γ-butenolide-type frameworks with high efficiency and valuable
Organocatalytic asymmetric direct vinylogous aldol reactions of γ-crotonolactone with aromatic aldehydes
作者:Sunil V. Pansare、Eldho K. Paul
DOI:10.1039/c0cc04191b
日期:——
The direct aldol reaction of γ-crotonolactone and various aromatic aldehydes is catalyzed by bifunctional aminothiourea and aminosquaramide organocatalysts to provide diastereomerically and enantiomerically enriched 5-substituted 2(5H) furanones (γ-butenolides). The reaction is a simple alternative to the classical vinylogous aldol reaction of silyloxy furans.