Acyl‐Phosphide Anions via an Intermediate with Carbene Character: Reactions of K[PtBu2] and CO. Issue 11 (6th February 2019)

• Record Type: Journal Article
• Authors: Xu, Maotong; Jupp, Andrew R.; Stephan, Douglas W.
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 11(2019)
• Page Start: 3548
• Page End: 3552
• Publication Date: 2019-02-06
• Subjects: anions -- carbenes -- migrations -- potassium -- structure elucidation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201814562
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The analogy of the reactivity of group 1 phosphides to that of FLPs is further demonstrated by reactions with CO, affording a new synthetic route to acyl‐phosphide anions. The reaction of [K(18‐crown‐6)][P t Bu2 ] (1 ) with CO affords [(18‐crown‐6)K⋅THF2 ][ Z ‐ t BuP=C( t Bu)O] (2⋅THF2 ) as the major product, and the minor product [K6 (18‐crown‐6)][( t Bu2 PCO)2 ]3 (3 ). Species 2 reacts with either BPh3 or additional CO to give [K(18‐crown‐6)][(Ph3 B) t BuPC( t Bu)O] (4 ) and [K(18‐crown‐6)][(OC t Bu)2 P] (5 ), respectively. The acyl‐phosphide anion 2 is thought to be formed by a photochemically induced radical process involving a transient species with triplet carbene character, prompting 1, 2‐ tert ‐butyl group migration. A similar process is proposed for the subsequent reaction of 2 with CO to give 5 . Abstract : Keeping it PC : The anion [P t Bu2 ] − reacts with CO to generate a transient intermediate with carbene character. This species undergoes either 1, 2‐alkyl migration or dimerization to form acyl‐phosphide anions. Similarly, one of these anions reacts further with CO to give a diacyl‐phosphide anion.