Bartolozzi Alessandra, Pacciani Stefania, Benvenuti Cecilia, Cacciarini Martina, Liguori Francesca, Menichetti Stefano, Nativi Cristina
Dipartimento di Chimica Organica Ugo Schiff, Universita' di Firenze, and CNR-ICCOM, via della Lastruccia, 13 I-50019 Sesto Fiorentino (FI), Italy.
J Org Chem. 2003 Oct 31;68(22):8529-33. doi: 10.1021/jo034556r.
A nonclassical, totally stereoselective synthesis of orthogonally protected 1,3-disaccharides is reported. Enantiomerically pure beta-keto-delta-lactones, efficiently obtained from glucal and galactal, are transformed into electron-poor heterodienes and chemo-, regio-, and stereoselectively cycloadded to glycals as electron-rich dienophiles, to directly afford 2-thiodisaccharides. The reductive desulfurization of the latter smoothly gave the corresponding 2,2'-dideoxydisaccharides.
报道了一种非经典的、完全立体选择性的合成正交保护的1,3-二糖的方法。从葡糖醛和半乳糖醛高效获得的对映体纯的β-酮-δ-内酯被转化为贫电子杂二烯，并作为富电子亲双烯体与糖烯进行化学、区域和立体选择性环加成，直接得到2-硫代二糖。后者的还原脱硫顺利得到相应的2,2'-二脱氧二糖。
