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Regioselective Simmons-Smith-type cyclopropanations of polyalkenes enabled by transition metal catalysis.

ABSTRACT: A [ i-PrPDI]CoBr2 complex (PDI = pyridine-diimine) catalyzes Simmons-Smith-type reductive cyclopropanation reactions using CH2Br2 in combination with Zn. In contrast to its non-catalytic variant, the cobalt-catalyzed cyclopropanation is capable of discriminating between alkenes of similar electronic properties based on their substitution patterns: monosubstituted > 1,1-disubstituted > (Z)-1,2-disubstituted > (E)-1,2-disubstituted > trisubstituted. This property enables synthetically useful yields to be achieved for the monocyclopropanation of polyalkene substrates, including terpene derivatives and conjugated 1,3-dienes. Mechanistic studies implicate a carbenoid species containing both Co and Zn as the catalytically relevant methylene transfer agent.

SUBMITTER: Werth J

PROVIDER: S-EPMC5890799 | biostudies-other | 2018 Feb

REPOSITORIES: biostudies-other

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Regioselective Simmons-Smith-type cyclopropanations of polyalkenes enabled by transition metal catalysis.

Werth Jacob J Uyeda Christopher C

Chemical science 20180102 6

A [ i-PrPDI]CoBr2 complex (PDI = pyridine-diimine) catalyzes Simmons-Smith-type reductive cyclopropanation reactions using CH2Br2 in combination with Zn. In contrast to its non-catalytic variant, the cobalt-catalyzed cyclopropanation is capable of discriminating between alkenes of similar electronic properties based on their substitution patterns: monosubstituted > 1,1-disubstituted > (Z)-1,2-disubstituted > (E)-1,2-disubstituted > ...[more]

PMID: 29675205

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