Au-Catalyzed Asymmetric Formal [3 + 2] Cycloaddition of Isocyanoacetates with Maleimides
摘要:
An efficient protocol for the Au-I-catalyzed asymmetric formal [3 + 2] cycloaddition of isocyanoacetates with phenylmaleimide has been developed. In the presence of cationic Au-I/DTBM-segphos complex, excellent diastereoselectivity and high levels of enantioselectivity (up to 97% cc) have been attained with a variety of alpha-substituted isocyanoacetates. The synthetic potential of the resulting enantioenriched 1-pyrrolines has been demonstrated by the preparation of highly substituted pyrrolidines bearing a quaternary stereocenter.