Synthesis 2019; 51(15): 2897-2908
DOI: 10.1055/s-0037-1612425
paper
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Sterically Congested Carbamates of Carbohydrates through Organic Base Catalysis

Anji Chen
,
Dan Wang
,
Lalith P. Samankumara
,
Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, USA   Email: g1wang@odu.edu
› Author Affiliations
We are grateful for financial support from a Boehringer Ingelheim Science Advancement grant and the National Science Foundation (grant CHE 1808609).
Further Information

Publication History

Received: 10 January 2019

Accepted after revision: 12 March 2019

Publication Date:
16 April 2019 (online)


Abstract

4,6-O-Benzylidene acetal protected α-methoxy d-glucose and d-glucosamine are useful building blocks for the syntheses of carbohydrate derivatives and functional molecular assemblies. In this research, we have developed a general method for the preparation of C-3 carbamate derivatives of densely functionalized glucose and glucosamine with isocyanates using organic bases as catalysts. Without a suitable catalyst, the C-3 hydroxy group of the glucosamine derivative could not be converted into the corresponding carbamates when treated with isocyanates. Several organic bases were screened as the catalysts for the reactions, and we discovered that 5.0 mol% of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was an effective catalyst for the carbamoylation reaction. A library of both alkyl and aryl carbamate derivatives of the two sterically congested carbohydrates have been effectively synthesized using the current method.

Supporting Information