Pd-Catalyzed Asymmetric Dearomative Cycloaddition for Construction of Optically Active Pyrroloindoline and Cyclopentaindoline Derivatives: Access to 3a-Aminopyrroloindolines

Asymmetric dearomative
[3 + 2] cycloaddition reactions of 3-nitroindoles
with vinyl aziridine and vinyl cyclopropanes have been respectively
successfully developed in the presence of a chiral box/Pd(0) complex.
A series of enantiomerically enriched 3a-nitro-hexahydropyrrolo­[2,3-b]­indole and 8b-nitrohexahydrocyclopenta­[b]­indole derivatives containing three contiguous chiral centers are
smoothly obtained in high yields with satisfactory regio-, chemo-,
and enantioselectivity. Remarkably, the synthetic utility of this
process was demonstrated through direct reductive amination and functionalization
of the carbon–carbon double bond of the desired products.