An expeditious synthesis of α-substituted tert-butyl acrylates from commercially available aldehydes and Meldrum’s acid has been established. The method benefits from a telescoped condensation-reduction sequence to afford 5-monosubstituted Meldrum’s acid derivatives followed by a Mannich-type reaction triggered by a rapid cycloreversion of the dioxinone ring on heating with tert-butyl alcohol.
Chiral diene-promoted room temperature conjugate arylation: highly enantioselective synthesis of substituted chiral phenylalanine derivatives and α,α-di(arylmethyl)acetates
作者:Jian-Ping Chen、Ming-Hua Xu
DOI:10.1039/d0ob00616e
日期:——
highly enantiocontrolled room temperature rhodium-catalyzed conjugate arylation process was developed. The reaction proceeds through 1,4-addition of α-substitutedacrylates followed by enantioselectiveprotonation using a C1-symmetric chiral bicyclo[2,2,2] diene as the ligand and water as the proton source. This exceptionally simple protocol provides a reliable and practical access to structurally important
Rhodium-Catalyzed Conjugate Addition−Enantioselective Protonation: The Synthesis of α,α‘-Dibenzyl Esters
作者:Christopher G. Frost、Stephen D. Penrose、Kim Lambshead、Paul R. Raithby、John E. Warren、Robert Gleave
DOI:10.1021/ol070603g
日期:2007.5.1
Alpha-benzyl acrylates, which are conveniently prepared from the corresponding aldehydes, can be employed as substrates in a tandemrhodium-catalyzed conjugate addition-enantioselective protonation protocol to afford enantiomerically enriched alpha,alpha'-dibenzyl esters. The synergistic effect of enantiopure ligand and proton source was rapidly optimized with use of a microwave reactor.