Germylene cyanide complex: a reagent for the activation of aldehydes with catalytic significance

The first example of a germanium(II) cyanide complex [GeCN(L)] (2) (L=aminotroponiminate (ATI)) has been synthesized through a novel and relatively benign route that involves the reaction of a digermylene oxide [(L)Ge-O-Ge(L)] (1) with trimethylsilylcyanide (TMSCN). Interestingly, compound 2 activates several aldehydes (RCHO) at room temperature and results in the corresponding cyanogermylated products [RC{OGe(L)}(CN)H] (R=H 3, iPr 4, tBu 5, CH(Ph)Me 6). Reaction of one of the cyanogermylated products (4) with TMSCN affords the cyanosilylated product [(iPr)C(OSiMe3 )(CN)H] (7) along with [GeCN(L)] quantitatively, and insinuates the possible utility of [GeCN(L)] as a catalyst for the cyanosilylation reactions of aldehydes with TMSCN. Accordingly, the quantitative formation of several cyanosilylated products [RC(OSiMe3 )(CN)H] (7-9) in the reaction between RCHO and TMSCN by using 1 mol % of [GeCN(L)] as a catalyst is also reported for the first time.