Highly diastereo- and enantioselective synthesis of spirooxindole-cyclohexaneamides through N,N′-dioxide/Ni(ii)-catalyzed Diels–Alder reactions†
Abstract
Highly efficient asymmetric Diels–Alder reactions of methyleneindolinones with 1,3-dienylcarbamates and 1,2-dihydropyridines have been accomplished by using a chiral N,N′-dioxide/nickel(II) complex as an efficient catalyst. New kinds of spirooxindole-cyclohexaneamides were achieved in up to 99% yield, >95 : 5 dr, and 99% ee.