Asymmetric Catalytic Synthesis of Hexahydropyrrolo-isoquinolines via Three-Component 1,3-Dipolar-Cycloaddition
Zhaojing Li1, Nian Xu1, Ning Guo1
1Key Laboratory of Green Chemistry &Technology Ministry of Education, College of Chemistry, Sichuan University, P. R. China.
Abstract:
An asymmetric three-component 1,3-dipolar cycloaddition of 3,4-dihydroisoquinolines, bromoacetates and α,β-unsaturated pyrazole amide is realized by using a chiral N,N'-dioxide-Y(OTf)3 complex as the catalyst. The process includes a base-promoted formation of dihydroisoquinolium ylides in situ, and a chiral Lewis acid-catalyzed asymmetric [3+2] cycloaddition with α,β-unsaturated pyrazole amides. A series of hexahydropyrrolo-isoquinolines are obtained in moderate to good yields with excellent diastereo- and enantioselectivities.
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