Phenyl Sulphonyl Acetaldehyde Diethyl Acetal: A New Robust 1,2-Diol Protective Group
作者:S. Chandrasekhar、Ch. Srinivas、P. Srihari
DOI:10.1081/scc-120016347
日期:2003.1.4
Abstract A simple preparation of a novel resilient protective group for 1,2-diols is described herein which is remarkably stable in the presence of extremely harsh basic conditions as well as acidic media. The title reagent's versatility is detailed with numerous examples. #IICT Communication No.: 4583.
A mild and efficient method for formation of methyleneacetals from 1,2- and 1,3-diols using methoxymethylphenylsulfide, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), and dibutylhydroxytoluene (BHT) is described. The use of BHT in this process suppresses side reactions and enables high-yielding formation of methyleneacetals of various diols, including carbohydrate-type substrates.
regiocontrolled protection of unsymmetrical 1,2- and 1,3-diols has been developed. Different types of protected diols are available from the methylene acetal in a one-pot procedure. Highly regioselective protection of diols with a silyl group at the less hindered hydroxy group as well as with a MOM group at the more hindered one were achieved. The reaction conditions are mild without affecting other functional
facile deprotection of methyleneacetal protection of diols under mild conditions is established. The combination of trimethylsilyl triflate (TMSOTf) and 2,2'-bipyridyl followed by a weakly acidic hydrolysis was effective and the substrates having acid sensitive functional groups can be tolerated under the stated conditions. The selective deprotection between methyleneacetal and benzophenone ketal