Frustrated Lewis Pair Induced Boroauration of Terminal Alkynes

摘要

Organoborane compounds are versatile reagents for organic synthesis. Various methods have been developed to incorporate boryl groups into organic frameworks. Among others, borometallation of alkynes, such as silaboration and stanna-boration, has received substantial attention in recent years. These reactions can introduce multiple functionalities in one step, providing an efficient way for the stereoselective synthesis of highly substituted alkenes. Whereas silaboration and stannaboration of alkynes often require transition-metal complexes as catalysts (Scheme 1a) the alkynes were reported to be able to directly insert into the M—B bond of boryl transition-metal complexes, resulting in the formation of (2-borylalkenyl)metal complexes (Scheme 1 b). One drawback of the abovementioned approaches is the requirement of boryl metal species, some of which are not easily accessible. Thus it will be highly interesting to develop a method through which the borometalation reaction can be directly achieved with hydroborane and metal complexes (Scheme 1 c).