在碱性或弱碱性条件下,通过硝酸铈铵(CAN)在MeCN / H 2 O或10%水溶液中进行环状缩醛和缩酮水解的可能性。甲醇被拒绝。然而,在pH 4.4下证明了Ce(IV)作为路易斯酸的作用。在这些条件下,允许环缩酮水解而糖苷键保持不变,还可以观察到由于空间位阻而引起的缩酮切割的选择性。当丙酮/水代替MeCN / H 2 O作为溶剂时,可获得相似的收率。
In the presence of a catalytic amount of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), acetals are readily hydrolysed to the corresponding aldehydes or ketones in aqueous acetonitrile under neutral conditions.
Mild and chemoselective catalytic deprotection of ketals and acetals using cerium(IV) ammonium nitrate
作者:Ali Ates、Arnaud Gautier、Bernard Leroy、Jean-Marc Plancher、Yannick Quesnel、Jean-Christophe Vanherck、István E Markó
DOI:10.1016/j.tet.2003.03.002
日期:2003.11
Cerium(IV) ammonium nitrate (CAN) is a powerful, though mild, reagent for the efficient and selective removal of a range of ketals and acetals. This novel deprotection method requires only catalytic amounts of CAN and tolerates a variety of functional and protecting groups. Mechanistic insights suggest that the Ce(IV) salts act as unique Lewis acids and not as redox active species.
New polyol ether compounds and a process for their preparation. The process comprises reacting a polyol, a carbonyl compound, and hydrogen in the presence of hydrogenation catalyst, to provide the polyol ether. The molar ratio of polyol to carbonyl compound in the process is greater than 5:1.
Dimethylboron bromide and diphenylboron bromide. Acetal and ketal cleavage. Cleavage of MEM, MOM, and MTM ethers.
作者:Yvan Quindon、Howard E. Morton、Christiane Yoakim
DOI:10.1016/s0040-4039(00)88238-6
日期:1983.1
A general and efficient procedure for the cleavage of acetals and ketals by the use of dimethylboron bromide or diphenylboron bromide is described. Under similar reaction conditions, MEM, MOM and MTM ethers also react to afford the parent alcohols in excellent yields.
Magnesium Bromide Mediated Selective Conversion of Acetals into Thioacetals
作者:Jung Ho Park、Sunggak Kim
DOI:10.1246/cl.1989.629
日期:1989.4
Magnesium bromide in ether is found to be a very effective and highly selective reagent for the conversion of acetals into the corresponding thioacetals in the presence of ketones.