Enantiospecific synthesis of ABC-ring system of A-nor and abeo 4(3 -> 2) tetra and pentacyclic triterpenes

Srikrishna, A and Babu, R Ramesh and Beeraiah, B (2010) Enantiospecific synthesis of ABC-ring system of A-nor and abeo 4(3 -> 2) tetra and pentacyclic triterpenes. In: Tetrahedron, 66 (4). pp. 852-861.

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Abstract

Enantiospecific synthesis of ABC-ring systems of A-nor and abeo 4(3 -> 2) tetra and pentacyclic triterpenes has been accomplished starting from the readily available monoterpene (R)-carvone. (R)-Carvone was used as the B-ring of the target molecules. A lithium-liquid ammonia mediated cyclisation of delta,epsilon-unsaturated ester was employed for the cyclopentannulation at the C-5 and C-6 carbons of carvone and an RCM reaction was employed for the cyclohexannulation to generate the ABC-ring system of A-nor tetra and pentacyclic triterpenes. The strategy has been extended for the synthesis of the ABC-ring system of abeo 4(3 -> 2) tetra and pentacyclic triterpenes. (C) 2009 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Triterpenes; A-nortriterpenes; Abeo triterpenes; Cyclopentannulation; Ring-closing olefin metathesis; Cyclohexannulation; Enatiospecific synthesis; Reductive allylation
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	25 Mar 2010 11:38
Last Modified:	19 Sep 2010 05:57
URI:	http://eprints.iisc.ernet.in/id/eprint/26223

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