Extension of hydrogen borrowing alkylation reactions for the total synthesis of (−)-γ-lycorane

Abstract

The total synthesis of (–)-γ-lycorane (10 steps) and synthesis of (±)-γ-lycorane (8 steps) was completed from cyclohexenone. A new two step hydrogen borrowing alkylation of an aziridinyl alcohol, coupled with a Ph* (Me₅C₆) deprotection/cyclisation procedure was developed for de novo formation of the fused 6,5 heterocyclic ring. This work is one of the first examples of hydrogen borrowing C–C bond formation being used as a key step in a total synthesis project.