Asymmetric Catalytic Synthesis of Epoxides via Three-Component Reaction of Diazoacetates, 2-Oxo-3-ynoates, and Nitrosoarenes.

An enantioselective three-component reaction of diazoacetates, 2-oxo-3-ynoates, and nitrosoarenes has been developed by using a chiral N,N'-dioxide/Ni(OTf)2 complex. This catalytic manifold allows rapid access to a series of multifunctional chiral epoxides containing an imino ketone substituent in moderate to good yields (up to 82%) and excellent diastereo- and enantioselectivities (up to >95/5 dr and 99% ee) with high levels of Z/E ratios (up to >95/5 Z/E) under mild reaction conditions.