posted on 2022-01-31, 17:36authored byXianjun Xu, Huangdi Feng, Xiaoyong Zhang, Liangliang Song, Luc Van Meervelt, Johan Van der Eycken, Jeremy N. Harvey, Erik V. Van der Eycken
A palladium-catalyzed
reaction of N-propargyl
oxazolidines with alkenes for the synthesis of indolizidines has been
developed. Through a sequential 6-exo-dig cyclization/proton
transfer/[3+2] cycloaddition/cycloreversion/aromatization process,
a series of fused polycyclic indolizines are obtained in moderate
to good yields with high functional group tolerance. Experimental
and theoretical studies suggest that the [3+2] cycloaddition/cycloreversion
of the oxazolidine ring probably involves C–C and C–O
bond cleavage, providing a new ring restructuring approach for the
synthesis of heterocycles.