Chiral N,N′-dioxide/Mg(OTf)2 complex-catalyzed asymmetric [2,3]-rearrangement of in situ generated ammonium salts

Catalytic enantioselective [2,3]-rearrangements of in situ generated ammonium ylides from glycine pyrazoleamides and allyl bromides were achieved by employing a chiral N,N '-dioxide/Mg-II complex as the catalyst. This protocol provided a facile and efficient synthesis route to a series of anti-alpha-amino acid derivatives in good yields with high stereoselectivities. Moreover, a possible catalytic cycle was proposed to illustrate the reaction process and the origin of stereoselectivity.