在室温下,在乙腈中作为催化剂的二溴化铜存在下,可以有效地实现乙缩醛向双(甲氧基苯基)甲基(BMPM)醚的反保护。使用双(甲氧基苯基)甲基异丙基醚(BMPMO i Pr)作为试剂,可以方便地将乙缩醛选择性地转化为相应的单保护二醇。这种新的实用试剂可在铜催化下将BMPM转移至1,3-二氧戊环或1,3-二氧六环。反应条件也非常温和并且耐受包括其他保护基团在内的各种官能团。
Three Solvent-Free Catalytic Approaches to the Acetal Functionalization of Carbohydrates and Their Applicability to One-Pot Generation of Orthogonally Protected Building Blocks
alternative protocols were developed to carry out the selective installation of acetal groups on carbohydrates and polyols under mildly acidic, solvent-freeconditions. One protocol is based on a diol/aldehyde condensation at room temperature, with an acetolysis process serving for the activation of the carbonyl component. A second approach is based on an orthoester-mediated activation of the carbonyl component