Chiral organotin hydrides containing intramolecular coordinating substituents

A series of chiral non-racemic triorganotin halides and triorganotin hydrides containing one or two (1R,2S,5R)-menthyl (Men) substituents as well as the 8-dimethylaminonaphthyl (L) or 2-[(1S)-1-dimethylaminoethyl]phenyl (L*) substituents has been synthesised and characterised. Each of the compounds MenPhLSnBr (1) and MenPhLSnH (2) has a stereogenic tin centre and the compounds were isolated in diastereomeric ratios of 60:40 and 66:33, respectively. Compounds MenPhL*SnCl (3) and MenPhL*SnH (4) were synthesised with diastereomeric ratios of 73:27 and 64:36, respectively. Single crystal X-ray analysis of MenPhL*SnCl (3), Men2L*SnCl (8), and MenPh2LSn (10) reveals that each structure has a tendency towards penta-coordination at the tin centre as a result of intramolecular N→Sn interactions. AM1 calculations successfully predict the molecular geometries observed in the solid state as well as the diastereomeric ratios observed in solution.