Synthesis and some properties of mixed alkyl(-)menthyltin dihydrides

VICTOR F.TERRAZA; DARÍO C. GERBINO; JULIO C. PODESTÁ

Basel

Conferencia; 19th Int. Electron. Conf. Synth. Org. Chem; 2015

Universidad de Santiago de Compostela

Organotin hydrides have found many applications in organic synthesis not only as reducing reagents [1] but also as intermediates in the generation of carbon-carbon bonds [2], and the synthesis of macrocycles via cyclohydrostannation [3]. Since one of the seminal papers on the reduction of carbonyl compounds with organotin hydrides (mono-, di-, and triorganotin hydrides) was published in 1961 [4], mainly the triorganotin hydrides (R3SnH) have been used routinely for the free radical reduction of alkyl halides and many other functional groups [1,2]. It should be mentioned that at present triphenyltin- and tri-n-butyltin hydrides are commercially available. Triorganotin hydrides containing mixed alkyl and (-)-menthyl ligands have been reported [5].On the other hand, there are less reports on the uses of diorganotin dihydrides (R2SnH2), mostly restricted to the use of Ph2SnH2 and n-Bu2SnH2 as reagents for the reduction of carbonyl compounds. We have not found reports on the synthesis of diorganotin dihydrides containing mixed alkyl and (-)-menthyl ligands.In this communication, we report the synthesis of several diorganotin dihydrides containing a bulky chiral (-)menthyl substituent and alkyl groups of increasing steric volume. The synthesis was carried out taking into account the reported sequence [6] for the easy of brominolysis of carbon-tin bonds of tetraalkyltins shown below.