Germylene Cyanide Complex: A Reagent for the Activation of Aldehydes with Catalytic Significance

• Published in: Chemistry : a European journal 2014-10, Vol.20 (42), p.13551-13556
• Main Authors: Siwatch, Rahul Kumar, Nagendran, Selvarajan
• Format: Article
• Language: English
• Subjects: Activation; Aldehydes; Catalysis; Catalysts; Chemistry; Cyanides; cyanogermylation; cyanosilylation; Formations; Germanium; germylene; Oxides; Reagents; Utilities
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201404204

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. Reaction of a digermylene oxide complex [(L)GeOGe(L)] (1) with trimethylsilylcyanide (TMSCN) gave the first germylene monocyanide [GeCN(L)] (2) (L=aminotroponiminate). Compound 2 catalyzes the cyanosilylation of aldehydes by using TMSCN and has become the first isolable and structurally characterized germylene to act as a catalyst (see scheme).