Carbohydrates and their analogues play a unique role in all living organisms and therefore have played a supremacy role in molecular recognition, energy supply, drug discovery, etc. During the last few decades, biocatalyst lipases have emerged as one of the greener and sustainable catalysts in comparison to traditional synthetic catalysts for the synthesis of modified carbohydrates and their analogues. Because lipase is a natural catalyst, it shows outstanding selectivity, reactivity, amazing tolerance, and assistance in carrying out eco-friendly greener methodology. The application of biocatalyst lipase as a chemo- and regio-selective catalyst is particularly relevant for organic chemists for the synthesis of modified carbohydrates, because carbohydrates contain several identical hydroxyl groups. Herein, we discussed the recent developments in the lipase Novozyme-435 mediated synthesis of modified carbohydrates and their biological significance.

In recent years, Sulfonyl hydrazides have emerged as powerful reagents for sulfonyl sources because of their easy availability, stability, and non-toxic nature. The hydrazinyl group can be easily detached from sulfonyl hydrazides using oxidative, thermal, radical, basic, or metal-catalyzed conditions. In this review, we have collected recent protocols for preparing sulfones, sulfides, and sulfoxides from the ideal starting material, sulfonyl hydrazides using various transition metals or in metal-free conditions.

The synthesis of novel C-4'-spiro-oxetano-α-L-ribonucleosides T and U in 39 and 45% overall yields have been achieved from 2',3',5'-tri-O-acetyl-4'-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosylthymine and 2',3',5'-tri-O-acetyl-4'-C-p-toluenesulfonyloxymethyl-β-D-xylofuranosyluracil, respectively. Both the tosylated nucleoside precursors have been synthesized following recently developed Novozyme®-435 catalyzed methodology.