01710nas a2200229   4500008004100000022001400041245019800055210006900253260010600322300001400428490000700442520074300449653002801192653001001220653002101230653002001251100001401271700002001285700001801305700002601323856013101349       2005                        eng d  a0040-403900aChiral 2-C-methylene glycosides and carbohydrate-derived pyrano[2,3-b][1]benzopyrans: synthesis via InCl3 catalyzed stereoselective ferrier rearrangement of 2-C-acetoxymethyl glycal derivatives0 aChiral 2Cmethylene glycosides and carbohydratederived pyrano23b1  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcNOV  a8047-80510 v463 a<p>2-C-Acetoxymethyl glycal derivatives react with aliphatic alcohols in the presence of InCl3 (30 mol %) to furnish the corresponding 2-C-methylene glycosides in excellent yields and with exclusive alpha-selectivity except for the methyl 2-C-methylene glycosides, which are formed in similar to 2:1 anomeric ratio in favour of the alpha-anomer. The reaction of 2-C-acetoxyglycals with phenols, however, produces the corresponding chiral carbohydrate-derived pyranobenzopyran derivatives via initial Ferrier rearrangement followed by tandem cyclization in excellent yields and moderate to high stereoselectivities in favour of the corresponding 10a-R-pyrano[2,3-b][1]benzopyran derivatives. (c) 2005 Elsevier Ltd. All rights reserved.</p>10a2-C-methylene glycoside10aInCl310apyranobenzopyran10aStereoselective1 aGhosh, R.1 aChakraborty, A.1 aMaiti, D., K.1 aPuranik, Vedavati, G.  uhttps://library.ncl.res.in/content/chiral-2-c-methylene-glycosides-and-carbohydrate-derived-pyrano23-b1benzopyrans-synthesis-1