Synthesis of N-acyl-N,O-acetals from N-aryl amides and acetals in the presence of TMSOTf
作者:C. Wade Downey、Alan S. Fleisher、James T. Rague、Chelsea L. Safran、Megan E. Venable、Robert D. Pike
DOI:10.1016/j.tetlet.2011.07.023
日期:2011.9
Secondary amides undergo in situ silyl imidate formation mediated by TMSOTf and an amine base, followed by addition to acetal acceptors to provide N-acyl-N,O-acetals in good yields. An analogous, high-yielding reaction is observed with 2-mercaptothiazoline as the silyl imidate precursor. Competing reduction of the acetal to the corresponding methyl ether via transfer hydrogenation can be circumvented by the replacement of CY2NMe with 2,6-lutidine under otherwise identical reaction conditions. (C) 2011 Elsevier Ltd. All rights reserved.
Photoredox Catalytic Access to <i>N</i>,<i>O</i>‐Acetals from Enamides by Means of Electron‐Poor Perylene Bisimides
Enamides can be converted into their N,O-acetals using just electron-poor perylene bisimides together with light, without the need for thiophenol as additive or strong acids as catalyst.