A Copper(I)-Catalyzed Addition/Annulation Sequence for the Two-Component Synthesis of γ-Ylidenebutenolides
作者:Sangwon Seo、Michael C. Willis
DOI:10.1021/acs.orglett.7b02151
日期:2017.9.1
A highly efficient Cu(I)-catalyzed addition/annulation sequence has been developed for the synthesis of (Z)-ylidenebutenolides employing readily available alpha-ketoacids and alkynes as substrates. The reactions employ a simple commercially available Cu(I)-catalyst, display good substrate scope, and deliver products with high stereoselectivity. The synthetic utility of the method is demonstrated by the straightforward derivatization of the ylidenebutenolides into a diverse range of heterocycles, and also by the preparation of the natural product bovolide, and analogs thereof.
Two-Step Synthesis of (Z)-3-Aryl-5-(arylmethylidene)butenolides by an Ivanov Reaction/Silver(I)-Catalyzed Lactonization/In Situ Dehydration Sequence
作者:Reinhard Brückner、David Hermann、Deniz Arican
DOI:10.1055/s-0036-1588338
日期:——
Dedicated to Professor Dieter Enders (RWTH Aachen) on the occasion of his 70th birthday Abstract A stereoselective synthesis of the title compounds was developed. Hexane- and amine-free THF solutions of α-lithiated lithium arylacetates (‘arylacetic acid dianions’) were aldol-added to 3-arylpropynals. This gave 2,5-diaryl-3-hydroxypent-4-ynoic acids with up to a 72:28 preference for the anti-diastereomer