Nucleophilic substitution results in inversion of configuration at the electrophilic carbon center (S 2) or racemization (S 1). The stereochemistry of the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secondary phosphine alkyl tosylates proceeded under mild conditions with inversion of configuration at the nucleophile to yield P-stereogenic syn-phosphiranes. DFT studies suggested that the novel stereochemistry results from acid-promoted tosylate dissociation to yield an intermediate phosphenium-bridged cation, which undergoes syn-selective cyclization.

We describe the synthesis of Fe(ii)-based coordination cages whose stability and gas adsorption properties can be tuned through structural modifications and redox reactivity.

An emerging challenge in nitrogen fixation catalysis is the formation of hydride species, which can play a role in catalyst deactivation and unproductive hydrogen evolution. A new pathway for productive N–H bond formation from an iron hydride precursor is described.