title: Stereodivergent route to the carbocyclic core of 2',3'-olefinic carbanucleosides: toward the synthesis of (L)-(+)- and (D)-(-)-carbovir.
abstract: (R)-2,3-Cyclohexylideneglyceraldehyde (1) has been elegantly exploited for a stereodivergent construction of the potential precursors (11a and 11b) of (L)-(+)- and (D)-(-)-carbovirs, respectively. The key steps in this approach were Luche's allylation of formaldehyde with allylic bromide 4c to produce 5 and ring-closing metathesis of 10b using Grubbs' first-generation catalyst to obtain 11. The moderate stereoselectivity of Luche's allylation reaction resulted in attaining stereodivergence in this approach which could be realized finally through easy chromatographic separation of the two isomers of the metathesis product to obtain homochiral precursors 11a and 11b in good amounts.
authors: Bio-Organic Division, Bhabha Atomic Research Center, Mumbai, India. achat@barc.gov.in
authors: Angshuman
authors: A
authors: Chattopadhyay
authors: Sibanarayan
authors: S
authors: Tripathy