A practical synthesis of 2-deoxy aldonolactones via a SmI2-mediated α-deoxygenation reaction
摘要:
A one-step deoxygenation of 2-hydroxylactones or their acetates is possible using samarium diiodide as an electron-transfer reagent in conjunction with a proton source.
Perbenzylated 1,7-dioxaspiro[5,5]undec-4-enederivatives of sugars are obtained in three steps, starting from fullyprotected glycono-1,5-lactones. The procedure is based on the attack of a lithiated dithiinyl reagent (6) on the starting δ-glyconolactone. The C-glycosidation leads to the sole thermodynamically more stable α-hemiacetal derivative, the spirocyclization of which is then accomplished with