Synthesis of 1,1‐Diborylalkenes through a Brønsted Base Catalyzed Reaction between Terminal Alkynes and Bis(pinacolato)diboron

Abstract

Abstract:A new method for the synthesis of 1,1-diborylalkenes through a Brønsted-base-catalyzed reaction between terminal alkynes and bis(pinacolato)diboron has been developed. The protocol allows direct synthesis of functionalized 1,1-diborylalkenes from various terminal alkynes including propiolates, propiolamides and 2-ethynylazoles.

Phosphine-catalyzed divergent reactivity of alkynoates with acid anhydrides: chemo- and stereoselective synthesis of polysubstituted olefins and dienes

“…Recently, the involvement of σ- type bonds of the electrophiles in reactions regarding alkynoates has also attracted considerable interests, resulting in a novel 1,2-difunctionalization of the alkyne moiety (Scheme 1b). For example, Sawamura and co-workers have pioneered the phosphine-catalyzed carboboration, 6 silaboration, 7 diboration, 8 as well as acylcyanation 9 of alkynoates with C–B, Si–B, B–B and C–CN σ- type bonds, respectively, which enabled facile syntheses of vinylboron and vinylnitrile derivatives. Very recently, a phosphine-catalyzed phosphinoboration of alkynoates with P–B containing electrophile such as phosphinoboronate to afford α-phosphino-β-boryl acrylate has also been documented by Santos.…”