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Synthesis of [3a,7a]-Dihydroindoles by a Tandem Arene Cyclopropanation/3,5-Sigmatropic Rearrangement Reaction.

ABSTRACT: Donor/acceptor carbenes provide a powerful platform for building molecular complexity, but the majority of their reactions have been limited to aryl and vinyl donor groups. We found that a N-containing donor/acceptor carbene precursor, 4-phthalimido- N-methanesulfonyl-1,2,3-triazole, reacts with unactivated arenes resulting in a mixture of [3+2]-cycloadducts, [3a,7a]-dihydroindoles, and formal C-H functionalization products in up to 82% yield upon heating. We also demonstrate that the formal C-H functionalization products arise from ring-opening of the [3+2]-cycloadducts. Computational studies suggest that the formal cycloaddition process takes places through a tandem arene cyclopropanation/6? electrocyclization/6? electrocyclic ring-opening/3,5-sigmatropic rearrangement reaction, which also accounts for the distinctive regioselectivity of the formal cycloaddition reaction.

SUBMITTER: Wilkerson-Hill SM

PROVIDER: S-EPMC7232103 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Synthesis of [3a,7a]-Dihydroindoles by a Tandem Arene Cyclopropanation/3,5-Sigmatropic Rearrangement Reaction.

Wilkerson-Hill Sidney M SM Haines Brandon E BE Musaev Djamaladdin G DG Davies Huw M L HML

The Journal of organic chemistry 20180625 15

Donor/acceptor carbenes provide a powerful platform for building molecular complexity, but the majority of their reactions have been limited to aryl and vinyl donor groups. We found that a N-containing donor/acceptor carbene precursor, 4-phthalimido- N-methanesulfonyl-1,2,3-triazole, reacts with unactivated arenes resulting in a mixture of [3+2]-cycloadducts, [3a,7a]-dihydroindoles, and formal C-H functionalization products in up to 82% yield upon heating. We also demonstrate that the formal C-H ...[more]

PMID: 29890080

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