Glycosidation of 3,4,6-Tri-O-Benzyl-2-Ethenyl-D-Glucal – A Route to 2-C-(β-Methyl)Methylene Glycosides
摘要:
Monosaccharidic and disaccharidic 2-C-(beta-methyl)methylene glycosides were synthesized by an electrophilic conjugate addition reaction of ROH-type compounds in the presence of Ph3+PH Br- to 2-ethenyl-3,4,6-tri-O-benzyl-D-glucal 1, functioning as a model glycosyl donor. This 2-vinyl glucal derivative represents a series of 2-vinyl, and 2-butadienyl glycals, prepared by Wittig-type methylenation of pyranosidic conjugated enals, derived from glucal, galactal and lactal. The exo-(beta-methyl)methylene group paves the way for further chemical transformations.
Stereoselective synthesis of 1,2-annulated-C-Aryl glycosides from carbohydrate-derived terminally unsubstituted dienes and arynes: Application towards synthesis of sugar-fused- or branched- naphthalenes, and C-Aryl glycosides
作者:Sateesh Dubbu、Ashish Kumar Verma、Kadigachalam Parasuraman、Yashwant D. Vankar
DOI:10.1016/j.carres.2018.06.001
日期:2018.7
Synthesis of 1,2-annulated-C-aryl glycosides has been achieved in a stereoselective manner through the Diels-Alder reaction between carbohydrate-derived terminally unsubstituted dienes and in situ generated arynes. In these reactions, formation of sugar-fused (or branched) naphthalenes was also observed and found to be temperature dependent and thus constituting one of the salient features of this