- Regioselective Simmons-Smith-type cyclopropanations of polyalkenes enabled by transition metal catalysis
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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.
- Werth, Jacob,Uyeda, Christopher
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p. 1604 - 1609
(2018/02/14)
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- Regioselectivity and Solvent Effects in Cyclopropanation of Alkadienes
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A comparison of the regioselectivities for monocyclopropanation of limonene and 4-vinylcyclohexene using diiodomethane with zinc dust and copper(I) chloride in ether, with diethylzinc in toluene, or with triethylaluminum in toluene-dichloromethane has bee
- Friedrich, Edwin C.,Niyati-Shirkhodaee, Fatemeh
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p. 2202 - 2205
(2007/10/02)
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