Nickel-Catalyzed Annulation of Donor-Acceptor Oxiranes with Imines: Diastereoselective Access to Highly Substituted 2,4-trans-Oxazolidines

An efficient approach for the synthesis of highly substituted 2,4-trans-oxazolidines has been achieved by means of nickel(II) chlorate hexahydrate [Ni(ClO4)(2)6H(2)O]-catalyzed [3+2]dipolar cycloaddition reactions of donor-acceptor oxiranes with imines via CC bond cleavage in good yields with moderate to high diastereoselectivity. The appropriate orientation of two activating ketones or esters is crucial for this chemoselective CC bond cleavage of the oxirane ring.