01946nas a2200241   4500008004100000022001400041245015400055210006900209260010600278300001400384490000700398520099100405653001401396653002101410653001401431653001201445653001601457653003001473100002601503700002601529700002301555856012601578       2011                        eng d  a0040-402000aSynthesis of C1- and C8a-epimers of (+)-castanospermine from D-glucose derived gamma,delta-epoxyazide: intramolecular 5-endo epoxide opening approach0 aSynthesis of C1 and C8aepimers of castanospermine from Dglucose   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAPR  a2773-27780 v673 a<p>A concise synthesis of two diastereomers of (+)-castanospermine namely 1- and 8a-epi-castanospermine 1b and 1c, respectively, is reported from D-glucose. The methodology involves stereoselective cross metathesis of D-glucose derived alkene 2 with 4-bromo-1-butene followed by azide displacement and m-CPBA oxidation to afford diastereomeric gamma,delta-epoxyazides 5a/5b. The Staudinger reaction of epoxyazide 5a followed by reaction with benzylchloroformate (CbzCl) unexpectedly furnished 1,3-oxazinan-2-one derivative 7 whose stereochemistry was establish by single crystal X-ray. This helps to assign the stereochemistry in the epoxidation reaction. The reduction of 5a/5b was then carried out by transfer hydrogenation to provide gamma,delta-epoxyamine that concomitantly undergoes intramolecular 5-endo-tet cyclization to afford hydroxypyrrolidine ring skeleton with sugar framework-a precursor to castanospermine analogues 1b/1c. (C) 2011 Elsevier Ltd. All rights reserved.</p>10aalkaloids10aCross metathesis10aD-Glucose10aEpoxide10aOxazinanone10aPolyhydroxy indolizidines1 aKalamkar, Navnath, B.1 aPuranik, Vedavati, G.1 aDhavale, Dilip, D.  uhttps://library.ncl.res.in/content/synthesis-c1-and-c8a-epimers-castanospermine-d-glucose-derived-gammadelta-epoxyazide-0