One-Pot Synthesis of Less Accessible N-Boc-Propargylic Amines through BF3-Catalyzed Alkynylation and Allylation Using Boronic Esters.

An efficient synthesis of α-alkynyl- or α-allyl-substituted N-Boc-propargylic amines is described via an alkynylation or allylation of alkynyl-substituted N-Boc-imines. Our strategy relies on the BF3-mediated in situ generation of alkynyl imines followed by alkynylation or allylation with the corresponding boronic esters. A range of less accessible N-Boc-propargylic amines were obtained in moderate to good yields under mild and acidic conditions with higher atom economy compared to the previous methods.