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Synthetic Applications of Carbohydrate-derived Donor-Acceptor Cyclopropanes

Ganesh, Venkataraman and Sridhar, Perali Ramu and Chandrasekaran, Srinivasan (2016) Synthetic Applications of Carbohydrate-derived Donor-Acceptor Cyclopropanes. In: ISRAEL JOURNAL OF CHEMISTRY, 56 (6-7, S). pp. 417-430.

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Official URL: http://dx.doi.org/10.1002/ijch.201500086

Abstract

In this account, we elaborate our group's contribution towards understanding the chemistry of carbohydrate-derived donor-acceptor (DA) cyclopropanes. Our work was mainly focused on the ring opening of these versatile chiral synthons under the influence of Lewis acid promoters like electrophilic halogen species, TMSOTf, BF3.OEt2, etc. We studied various modes of ring opening on these DA cyclopropanes, envisaging the access to intriguing molecular architectures. These modes of reaction of the DA cyclopropanes can be controlled by strategically introducing an electron-withdrawing group (EWG) onto the cyclopropane ring, which could direct the ring cleavage by polarizing the cyclopropane C-C bond. Our studies also revealed that the ring opening is sluggish in the absence of an EWG. Using this concept, we demonstrated the synthesis of various biologically interesting molecular skeletons, viz., glycoamino acids (GAA), GAA nucleotides, -levoglucosan amino acid, and septano-oligosaccharides, with high selectivity. We also applied our understanding to the first stereoselective synthesis of (S)-(-)-longianone and confirmed its absolute configuration. Apart from the inherently activated DA cyclopropanes, we introduced the in situ generation of DA cyclopropanes, starting from vinylcyclopropanes (VCPs). The ring-opening and ring-expansion chemistry of these easily accessible synthons was studied. The chemistry developed for carbohydrate-fused cyclopropanes was also applied for carbohydrate-derived spiro-cyclopropanes. The Lewis-acid-mediated ring opening of spiro-DA-cyclopropanes enabled easy access to fused furopyrans and spirolactones.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the WILEY-V C H VERLAG GMBH, POSTFACH 101161, 69451 WEINHEIM, GERMANY
Keywords: C-glycosides; cyclopropanes; glycoamino acids; oligosaccharides; spiro compounds
Department/Centre: Division of Chemical Sciences > Organic Chemistry
Depositing User: Id for Latest eprints
Date Deposited: 22 Aug 2016 09:45
Last Modified: 22 Aug 2016 09:45
URI: http://eprints.iisc.ac.in/id/eprint/54495

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