Pd‐Catalyzed Synthesis of Aryl Esters Involving Difluorocarbene Transfer Carbonylation

Abstract

A Pd‐catalyzed three‐component intermolecular reaction between aryl halides, ClCF2COONa and phenols is developed. A series of aryl benzoates were synthesized in up to 84% yield via difluorocarbene transfer carbonylation. It is devoted to acquiring the targeted products by construction of new C‐C, C=O and C‐O bonds in a one‐pot, one‐step process. The feature of this method includes the use of readily available starting materials, showing outstanding resistance to spatial obstruction and simple operation procedure with mild reaction conditions. Therefore, this makes the methodology a useful alternative to other schemes typically used for the synthesis of aryl esters.

Synthesis of 2-fluorinated pyrazolo[1,5-a]pyridines via base- mediated [3+2] cycloaddition of N-aminopyridinium salts with gem-difluorostyrenes

“…8 The cyclizations of gem - difluoroalkenes also have become particularly useful methods for the preparation of various polycyclic arenes and heterocyclic compounds. 9 Based on our previous works on difluorocarbene, 10 we initiated a program focusing on the construction of fluorinated nitrogen-containing heterocyclic molecules with gem -difluorostyrenes prepared from aldehydes and difluorocarbene precursors. Herein, we described that the base-promoted [3+2] cyclization mode between N -aminopyridinium salts with gem -difluorostyrenes to access functionalized 2-fluoro-pyrazolo[1,5- a ]pyridines with excellent chemoselectivity (Scheme 1b).…”