Synthesis and some properties of mixed alkyldi-(–)-menthyltin hydrides

Abstract

The synthesis and physical properties of methyldi-(–)-menthyltin 4 and neophyldi-(–)-menthyltin 7 hydrides as well as those of their organotin precursors are described. The reaction of hydrides 4 and 7 with carbon tetrachloride shows that the reactivity of 4 is within the range of the more common triorganotin hydrides while the organotin hydride 7 reacts more slowly. A study of the reduction of acetophenone with both hydrides shows that whereas the reduction with 4 leads to (–)-(S)-1-phenylethanol (8.8% optical purity), the reduction with 7 affords (+)-(R)-1-phenylethanol (6.6% optical purity); these results indicate that some degree of asymmetric induction can be achieved. Full ¹H, ¹³C and ¹¹⁹Sn NMR data are given.