Stable Ketenyl Anions via Ligand Exchange at an Anionic Carbon as Powerful Synthons**
Rui Wei, Xin‐Feng Wang, David A. Ruiz, Liu Leo Liu
Abstract
Abstract Under an atmosphere of carbon monoxide (CO), a (phosphino)diazomethyl anion salt [[P]‐CN 2 ][K(18‐C‐6)(THF)] ( 1 ) ([P]=[(CH 2 )(NDipp)] 2 P; 18‐C‐6=18‐crown‐6; Dipp=2,6‐diisopropylphenyl) undergoes a facile N 2 /CO exchange reaction giving the (phosphino)ketenyl anion salt [[P]‐CCO][K(18‐C‐6)] ( 2 ). Oxidation of 2 with elemental Se affords the (selenophosphoryl)ketenyl anion salt [P](Se)‐CCO][K(18‐C‐6)] ( 3 ). These ketenyl anions feature a strongly bent geometry at the P‐bound carbon and this carbon atom is highly nucleophilic. The electronic structure of the ketenyl anion [[P]‐CCO] − of 2 is examined by theoretical studies. Reactivity investigations demonstrate 2 as a versatile synthon for derivatives of ketene, enolate, acrylate and acrylimidate moieties.