Biswajit Sinha

Novel Synthesis of OxathiocineDerivatives by Wittig Olefination and Intramolecular HeckReaction via an 8-endo-trig Cyclization

Syntheses of hitherto unreported heterocycles, such as oxathiocine derivatives, in excellent yields, and a doubly cyclized oxathiocine derivative, through a Wittig olefination and intramolecular Heck reaction sequence via an unusual 8-endo-trig cyclization, are reported.

Synthesis of 3-iodopyrrolocoumarins via iodine-induced 5-endo-dig electrophilic cyclization

An efficient synthesis of 3-iodopyrrolocoumarins has been achieved by a simple and straightforward strategy involving palladium–copper-catalyzed Sonogashira coupling followed by iodocyclization at ambient temperature using molecular iodine as the electrophilic source. In addition, functionalization at the 3-position of the iodocyclized product is performed via Sonogashira reaction.Graphical abstract

Coinage metals (Cu, Ag and Au) in the synthesis of natural products

The chemistry of natural products has emerged as an extremely important area of contemporary research owing to their profound biological activities, complex molecular architecture with challenging stereochemistry and potential for use as medicine. Searches for efficient synthetic procedures for natural products, drugs, and materials with economical and ecological advantages are important areas of current research interest. This article describes the isolation, bioactivity and synthesis of several natural products and drugs by employing coinage metal-catalyzed/mediated reaction/strategy either in a sequential or a domino fashion. We have made an attempt to summarize the progress made in the area from 2008 onwards.