Nucleophilic arylation with tetraarylphosphonium salts

• Published in: Nature communications Vol. 7; no. 1; p. 10337
• Main Authors: Deng, Zuyong, Lin, Jin-Hong, Xiao, Ji-Chang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 29.01.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/403/933; Aldehydes; Carbonyl compounds; Humanities and Social Sciences; multidisciplinary; Reagents; Salts; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10337

Organic phosphonium salts have served as important intermediates in synthetic chemistry. But the use of a substituent on the positive phosphorus as a nucleophile to construct C–C bond remains a significant challenge. Here we report an efficient transition-metal-free protocol for the direct nucleophilic arylation of carbonyls and imines with tetraarylphosphonium salts in the presence of caesium carbonate. The aryl nucleophile generated from phosphonium salt shows low basicity and good nucleophilicity, as evidenced by the successful conversion of enolizable aldehydes and ketones. The reaction is not particularly sensitive to water, shows wide substrate scope, and is compatible with a variety of functional groups including cyano and ester groups. Compared with the arylmetallic reagents that are usually moisture sensitive, the phosphonium salts are shelf-stable and can be easily handled. Carbon based nucleophiles often are synthetically limited by the high basicity/reactivity of the starting materials. Here, the authors show that tetraarylphosphonium salts can be induced to act as C-aryl nucleophiles for the addition to carbonyls and imines.