Asymmetric synthesis of enantio-enriched acyclic α-amino alkylstannanes and rearrangement behavior of carbanions thereof

An efficient stereocontrolled synthesis of enantio-enriched N-Boc-N-allyl-α-amino alkylstannanes and N,N-diallylic α-amino alkylstannanes starting from enantio-enriched α-hydroxy alkylstannane has been developed. The aza-Wittig rearrangement of enantio-defined N,N-diallyl-α-amino alkyllithium, generated by tin–lithium exchange, is shown to proceed predominantly with inversion of configuration at the Li-bearing carbon terminus.