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Scientific article
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Enantioselective formation of bicyclic lactones by rhodium-catalyzed intramolecular CH-insertion reactions

Published inHelvetica chimica acta, vol. 77, no. 3, p. 645-654
Publication date1994
Abstract

The decomposition of cyclohexyl diazoacetate (5a) in the presence of the chiral [Rh2{(2S)-mepy}4] catalyst leads to a 3:1 cis/trans mixture of bicyclic lactone 6a with an enantiomeric excess of 95–97% (cis) and 90% (trans). The conformationally rigid tert-butyl derivatives 5b and 5c afford, in the presence of the same catalyst, 6b and 6c, respectively, via insertion into the equatorial C-H bonds exclusively, with ee's of ca. 95%. A remarkable degree of induction (92–95%) results in the lactone 6g upon decomposition of 1-isopropyl-2-methylpropyl diazoacetate (5g). The diazoacetates derived from 1-methylcyclohexanol, cyclopentanol and 1-methylcyclopentanol (5d–f) afford under similar conditions insertion products with higher diastereoselectivity, but significantly lower enantioselectivity. Other dirhodium catalysts are less efficient.

Citation (ISO format)
MULLER, Paul, POLLEUX, Philippe. Enantioselective formation of bicyclic lactones by rhodium-catalyzed intramolecular CH-insertion reactions. In: Helvetica chimica acta, 1994, vol. 77, n° 3, p. 645–654. doi: 10.1002/hlca.19940770307
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ISSN of the journal0018-019X
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