Sun D, Zhang H, Gao J, Guan X, Qin X, Jiang G, Zhang G, Zheng L, Zhang S. Asymmetric Synthesis of Spiro[3,2'-morpholine-oxindoles] Derivatives via the [5 + 1] Annulation Reaction.
J Org Chem 2021;
86:16815-16823. [PMID:
34761939 DOI:
10.1021/acs.joc.1c02037]
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Abstract
An efficacious method in which BINOL-type chiral imidodiphosphoric acid catalyzed the asymmetric [5 + 1] annulation reaction of 2-pyrrolylphenol with 1-methylindoline-2,3-dione was established. The strategy tolerated a broad substrate scope, and 30 examples were obtained. A range of enantioenriched spiro[3,2'-morpholine-oxindole] derivatives which incorporate a tertiary stereocenter, with moderate to excellent yields (up to 96%) and enantioselectivities (up to 99%) under mild conditions, was delivered.
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