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The imide moiety is a well-known structural motif in bioactive compounds and a useful building block in a variety of processes. Using N -acylglutarimides with MN(SiMe 3 ) 2 and either N -acylpyrroles or aryl esters, an operationally convenient method to produce a wide array of diaryl- and alkyl arylimides is presented. Symmetric imides are also accessible when N -acylglutarimides are employed as acylation reagents under similar reaction conditions. A unique feature of this method stems from the use of two different electrophilic acylating reagents leading to the formation of the unsymmetrical imides with excellent chemoselectivity.
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N -Acyl pyrroles: chemoselective pyrrole dance vs. C–H functionalization/aroylation of toluenes
Chemoselectivity is one of the most challenging issues facing the chemical sciences. In this study, the first highly chemoselective reactions of N -acylpyrroles via either an anionic Fries rearrangement (pyrrole dance) or a C–H functionalization of toluene to provide aryl benzyl ketones are advanced. This efficient and operationally simple approach enables the synthesis of either 2-aroylpyrroles or aryl benzyl ketones in good to excellent yields under transition metal-free conditions. The choice of base plays a crucial role in controlling the chemoselectivity. The aroylation of toluene derivatives was observed with N -acylpyrroles when subjected to KN(SiMe 3 ) 2 , while anionic Fries rearrangement products were produced with LiN(SiMe 3 ) 2 . Surprisingly, cross-over experiments indicate that the anionic Fries rearrangement is an intermolecular process. The aroylation reaction has the advantage over Weinreb amide chemistry in that it does not require preformed organometallic reagents or cryogenic temperatures.
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- Award ID(s):
- 1902509
- PAR ID:
- 10348060
- Date Published:
- Journal Name:
- Organic Chemistry Frontiers
- Volume:
- 8
- Issue:
- 21
- ISSN:
- 2052-4129
- Page Range / eLocation ID:
- 6000 to 6008
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D1QO00944C
