Ir(ppy)<sub>3</sub>-Catalyzed, Visible-Light-Mediated Reaction of α-Chloro Cinnamates with Enol Acetates: An Apparent Halogen Paradox
作者:Thomas Föll、Julia Rehbein、Oliver Reiser
DOI:10.1021/acs.orglett.8b02484
日期:2018.9.21
activation of vinyl chloridesderivedfrom α-chloro ethyl cinnamates via oxidative quenching of excited photocatalyst fac-Ir(ppy)3 is described. Upon photoelectron transfer and chloride extrusion, the corresponding vinyl radical can be efficiently trapped by enol acetates, giving rise to synthetically useful 1,4-dicarbonyl compounds in good to excellent yields. This transformation is distinguished by
Novel Base-Free Catalytic Wittig Reaction for the Synthesis of Highly Functionalized Alkenes
作者:Marie-Luis Schirmer、Sven Adomeit、Anke Spannenberg、Thomas Werner
DOI:10.1002/chem.201503744
日期:2016.2.12
base‐free catalytic Wittigreactions has been developed and optimized. Initially, several potential (pre)catalysts as well as different silanes as reducing agents were screened. A system based on a readily available phosphine oxide as precatalyst and trimethoxy silane as reducing agent proved to be optimal. The effect of various Brønsted acidic additives was studied. Subsequently, the reaction conditions were
Synthesis of multi-functional alkenes via Wittig reaction with a new-type of phosphorus ylides
作者:Yi-Ling Tsai、Siang-en Syu、Shu-Mei Yang、Utpal Das、Yu-Shiou Fan、Chia-Jui Lee、Wenwei Lin
DOI:10.1016/j.tet.2014.06.015
日期:2014.8
A Bu3P-mediated mild and efficient synthesis of multi-functional alkenes has been described starting from substituted acrylate with aldehydes. In situ generated zwitterionic intermediates underwent proton-exchange to afford ylide intermediates, which were trapped by corresponding aldehydes providing the products in up to 92% yield with complete E-stereoselectivity. Further derivatization of the products