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 i-Pr2NEt with 2,6-lutidine under otherwise identical reaction conditions.
Copyright © 2011, Elsevier. The definitive version is available at: http://www.journals.elsevier.com/tetrahedron-letters.
Downey, C. Wade, Alan S. Fleisher, James T. Rague, Chelsea L. Safran, Megan E. Venable, and Robert D. Pike. "Synthesis of N-Acyl-N,O-Acetals from N-Aryl Amides and Acetals in the Presence of TMSOTf." Tetrahedron Letters 52, no. 37 (September 12, 2011): 4756-759. doi:10.1016/j.tetlet.2011.07.023.
Downey, C. Wade; Fleisher, Alan S.; Rague, James T.; Safran, Chelsea L.; Venable, Megan E.; and Pike, Robert D., "Synthesis of N-Acyl-N,O-Acetals from N-Aryl Amides and Acetals in the Presence of TMSOTf" (2011). Chemistry Faculty Publications. Paper 12.