A Useful and Catalytic Method for Protection of Carbonyl Compounds into the Corresponding 1,3-Oxathiolanes and Deprotection to the Parent Carbonyl Compounds
A Useful and Catalytic Method for Protection of Carbonyl Compounds into the Corresponding 1,3-Oxathiolanes and Deprotection to the Parent Carbonyl Compounds
作者:Ejabul Mondal、Priti Rani Sahu、Abu T. Khan
DOI:10.1055/s-2002-20466
日期:——
A wide variety of carbonyl compounds 1 can be easily protected to the corresponding 1,3-oxathiolanes 2 in good yields in the presence of catalytic amount of perchloric acid in dry CH2Cl2 at 0-5 °C. On the other hand, various 1,3-oxathiolanes 2 can be selectively deprotected to the parent carbonyl compounds 1 in very good yields by H2MoO4·H2O-H2O2 catalyzed oxidation of ammonium bromide in the presence of perchloric acid in CH2Cl2-H2O solvent system. Mild reaction condition, high selectivity, efficient and relatively good yields are some of the major advantages of the procedure.
A Highly Efficient Procedure for Regeneration of Carbonyl Groups from their Corresponding Oxathioacetals and Dithioacetals Using Sodium Nitrite and Acetyl Chloride in Dichloromethane
作者:Abu T. Khan、Ejabul Mondal、Priti R. Sahu
DOI:10.1055/s-2003-37115
日期:——
A wide variety of oxathioacetals 1 as well as dithioacetals 2 can be chemoselectively deprotected to the corresponding carbonyl compounds 3 in good yields by employing NaNO2-AcCl and H2O in CH2Cl2 at 0 °C to room temperature. Some of the major advantages of this procedure are: mild conditions, easy to handle, highly chemoselective and efficient, high yields and inexpensive reagents. In addition, no acetylation occurs at the hydroxyl group nor chlorination takes place at the double bond.
An Efficient Method for One-Pot Reductive Cleavage of Acetals to Primary Alcohols Using a Bimetal Redox Couple CoCl2.6H2O-Zn
作者:Kuladip Sarma、Amrit Goswami
DOI:10.2174/157017809789869456
日期:2009.10.1
Acyclic or cyclic O,O-acetals and O,S-acetals underwent reductivecleavage to give primary alcohols efficiently on treatment with Zn-CoCl2.6H2O-bimetal redox system in dry tetrahydrofuran at ambient temperature to give good to excellent yields.
A useful and convenient synthetic protocol for interconversion of carbonyl compounds to the corresponding 1,3-oxathiolanes and vice versa employing organic ammonium tribromide (OATB)
作者:Ejabul Mondal、Priti Rani Sahu、Gopal Bose、Abu T. Khan
DOI:10.1016/s0040-4039(02)00345-3
日期:2002.4
A wide variety of carbonyl Compounds I can be easily protected selectively as the corresponding 1.3-oxathiolanes 2 in good yields using a catalytic amount (0.01-0.1 equiv.) of n-tetrabutylammonium tribromide in dry CH2Cl2 at 0-5 degreesC. On the other hand, various 1,3-oxathiolanes 2 can be deprotected chemoselectively to the parent carbonyl compounds I employing 0.5 equivalents of organic ammionum tribromides under identical conditions in verb high yields. Mild conditions, high selectivity and yield, highly efficient. less expensive, and no brominations either at the double bond or allylic position and even alpha- to the keto position or aromatic ring are some of the major advantages of the protocol. (C) 2002 Elsevier Science Ltd. All rights reserved.