N-Heterocyclic Germylene and Stannylene Catalyzed Cyanosilylation and Hydroboration of Aldehydes

Recent years have witnessed a significant growth in the area of low-valent main-group compounds due to their potential to activate small molecules. However, there is a paucity of examples of low-valent main-group compounds being used as single-site catalysts for organic transformations. This study represents the hydroboration and cyanosilylation reactions of a range of aldehydes by a benzannulated heavier N-heterocyclic germylene (1) and stannylene (2) under mild conditions. A wide variety of substrate scope was studied. The mechanistic pathway of the cyanosilylation reaction is initiated through the coordination of TMSCN with the catalyst followed by the attack of aldehydes. Conversely, hydroboration proceeds via formation of a donor-acceptor adduct between HBpin and the catalyst. Experimental and theoretical studies were performed to establish the mechanism.