Recent advances in the use of tri(2-furyl)germane, triphenylgermane and their derivatives in organic synthesis

Tri(2-furyl)germane is a readily prepared, easy-to-handle, and storable triorganogermane. The three 2-furyl groups confer unique reactivity on it in a variety of reactions. Tri(2-furyl)germane is a promising alternative to tributyltin hydride in radical reaction, especially superior in radical addition to alkenes. The hydrogen of tri(2-furyl)germane is so acidic that generation of the corresponding germyl anion is achieved with the aid of weak bases, such as potassium tert-butoxide and cesium carbonate. The anion participates in nucleophilic addition to aldehydes, 1,4-addition to α,β-unsaturated carbonyl compounds, and coupling reaction with aryl and vinyl halides under palladium catalysis. Palladium-catalyzed hydrogermylation with tri(2-furyl)germane create some novel phenomena. Some chemistry of triphenylgermane will be described.