Direct Substitution of Primary Allylic Amines with Sulfinate Salts

摘要

The NH_2 group in primary allylic amines was substituted directly by sulfinate salts with excellent regio- and stereoselectivities. In the presence of 0.1 mol % [Pd(allyl)Cl]-2, 0.4 mol % l,4-bis(diphenylphosphino)-butane (dppb), and excess boric acid, a range of α-unbranched primary allylic amines were smoothly substituted with sodium sulfinates in an α-selective fashion to give structurally diverse allylic sulfones in good to excellent yields with exclusive E selectivity. Replacing dppb with 1,1'-bi-2-naphthol (BINOL) allowed unsymmetric a-chiral primary allylic amines to be transformed into the corresponding allylic sulfones in good to excellent yields with excellent retention of ee. Importantly, the reaction complements known asymmetric methods in substrate scope via its unique ability to provide α-chiral allylic sulfones with high optical purity starting from unsymmetric allylic electrophiles.