DBU-catalyzed condensation of acyldiazomethanes to aldehydes in water and a new approach to ethyl β-hydroxy α-arylacrylates
摘要:
DBU-catalyzed condensation of ethyl diazoacetate (EDA) with aldehydes in pure water afforded corresponding beta-hydroxy alpha-diazo carbonyl compounds. The beta-hydroxy group of the products was further converted into beta-siloxy group. The Rh(II)-catalyzed reaction of the beta-aryl beta-siloxy alpha-diazo carbonyl compounds gave 1,2-aryl shift products predominantly. The three-step transformation constitutes an efficient synthesis of ethyl beta-hydroxy alpha-arylacrylates. (c) 2006 Elsevier Ltd. All rights reserved.
Palladium(0)-catalyzed rearrangement of allyl enol ethers to form chiral quaternary carbon centers via asymmetric allylic alkylation
作者:Nazim Uddin、Mizzanoor Rahaman、Eduardo Alberch、Sharif A. Asad、M. Mahmun Hossain
DOI:10.1016/j.tetlet.2018.07.065
日期:2018.9
Herein we report the first palladium(0)-catalyzed asymmetric allylic alkylation (AAA) of allyl enol ether via π-allylpalladium intermediate using Trost chiral diphosphine. This unprecedented reaction produced very rare α-aryl quaternary aldehydes with multi-functional groups. The main novelty in the chemistry demonstrates that enol ethers can be used as precursors for π-allylpalladium intermediates