Toward (Z)-selective Horner–Wadsworth–Emmons reaction of aldehydes with 2-fluoro-2-diethylphosphonoacetic acid
作者:Shigeki Sano、Rie Teranishi、Yoshimitsu Nagao
DOI:10.1016/s0040-4039(02)02269-4
日期:2002.12
The stereoselective Horner-Wadsworth-Emmons reaction of aldehydes with 2-fluoro-2-diethylphosphonoacetic acid utilizing i-PrMgBr afforded (Z)-alpha-fluoro-a,beta-unsaturated carboxylic acids as the major products. (C) 2002 Elsevier Science Ltd. All rights reserved.
Asymmetric Photodeconjugation: Highly Stereoselective Synthesis of α-Fluorocarboxylic Derivatives
作者:Frédéric Bargiggia、Sylvia Dos Santos、Olivier Piva
DOI:10.1055/s-2002-20028
日期:——
Irradiations of α-fluoro-α,β-unsaturated esters lead to the corresponding α-fluoro-β,γ-unsaturated isomers in good yields. The reaction required the use of an achiral base (typically an amine) to promote the protonation of the photodienolic intermediate. By replacing the ethyl group with a diacetone-d-glucose moiety, the reaction can be carried out in a diastereoselective manner to furnish the deconjugated esters with similar yields and selectivities up to 95%. The adducts were submitted to osmylation conditions to deliver α-fluoro-β-hydroxy-butyrolactones in one single step.