The catalytic asymmetric dearomatization of tryptamine for accessing meso-contiguous quaternary carbon centers of oligomeric cyclotryptamine alkaloids: a formal synthesis of hodgkinsine B. Issue 13 (22nd April 2021) - Wei, Hongbo
Abstract : Herein, we disclosed a catalytic asymmetric dearomatization (CADA) of tryptamine via tandem [4 + 2] cycloaddition/cyclization with o -azaxylylene in situ generated from functionalized 3-bromooxindole promoted by chiral N, N ′-dioxide/Ni(BF4 )2 . Abstract : Herein, we disclosed a catalytic asymmetric dearomatization (CADA) of tryptamine via tandem [4 + 2] cycloaddition/cyclization with o -azaxylylene in situ generated from functionalized 3-bromooxindole promoted by chiral N, N ′-dioxide/Ni(BF4 )2 . A variety of dimeric tryptamine derivatives with meso -contiguous quaternary carbon centers were obtained with good to excellent enantioselectivities and diastereoselectivities from N a -unprotected or protected tryptamines. A formal asymmetric synthesis of hodgkinsine B was also executed to showcase its synthetic potential.