Predicting phosphirane air stability using density functional theory

Abstract

Phosphorus 3‐membered heterocycles, phosphiranes, provide an interesting synthetic scaffold with a potentially diverse range of reactions that are currently underexplored. This is in part due to their difficulty in synthesis, with many products and intermediates containing low air stability. With the application and extension of a density functional theory (DFT) model to phosphiranes by calculation at the UB3LYP/6‐31G(d) level of their radical cation singly occupied molecular orbital (SOMO), a correlation between calculated and relative experimental air stability has been demonstrated. The model also accounts for the stability of many synthesised substituted and unsubstituted phosphiranes and has allowed new synthetic targets to be identified, in particular, 1‐(2,4,6‐tri‐tert‐butoxyphenyl)phosphirane exhibited high theoretical air stability. Because of the simplicity and efficiency of the model, its application enables phosphiranes to be screened for high bench stability, providing accessibility for their use in synthetic chemistry, in turn, realising the potential for incorporation of phosphiranes into complex synthetic strategies.