SnCl<sub>4</sub> Promoted Efficient Cleavage of Acetal/Ketal Groups with the Assistance of Water in CH<sub>2</sub>Cl<sub>2</sub>
Tao Luo,
Tian-Tian Xu,
Yang-Fan Guo,
Hai Dong
Affiliations
Tao Luo
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China
Tian-Tian Xu
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China
Yang-Fan Guo
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China
Hai Dong
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure, School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Luoyu Road 1037, Wuhan 430074, China
Acetalization and deacetalation are a pair of routine manipulations to protect and deprotect the 4- and 6-hydroxyl groups of glycosides in the synthesis of glycosyl building blocks. In this study, we found that treatment of SnCl4 with various carbohydrates containing acetal/ketal groups with the assistance of water in CH2Cl2 led to deacetalization/deketalization products in almost quantitative yields. In addition, for substrates containing both acetal/ketal and p-methoxylbenzyl groups, we also found that the p-methoxylbenzyl group was selectively cleaved by the use of a catalytic amount of SnCl4, while the acetal/ketal groups remained. Furthermore, based on this, 4,6-benzylidene glycosides can be conveniently converted to 4,6-OAc or 4-OH, 6-OAc glycosides.
