Exploring the Catalytic Radical Reactivity of Diazaphospholenes

Abstract

A subset of N-heterocyclic phosphines known as 1,3,2 diazaphospholenes (DAPs) have amassed significant attention over recent years. DAPs are excellent reduction catalysts for carbonyls, imines, pyridines, and enoates by virtue of being a strong hydride donors. N-heterocyclic phosphines are also known to engage in radical reactions such as carbon-carbon bond formation, hydrodehalogenations, and deoxygenation chemistry by hydrogen atom transfer. This thesis will present the first catalytic C-C bond forming intramolecular cyclization by diazaphospholene hydrides (DAP-H) generated in-situ from diazaphospholene bromides (DAP-Br). The catalysis is done without requiring a radical initiator, at room temperature, with 10% catalyst loading, and with the use of LED lights. A substrate scope examined using this chemistry showed that product formations were tolerant of some common functional groups. This work was followed by attempts at intermolecular alkylation chemistry, using the same conditions as in the former.