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Abstract A versatile method for the Suzuki‐Miyaura cross‐coupling of amides using highly active, well‐defined, and air‐stable Pd−phosphine precatalysts is reported. Most notably, the method represents the first example of using practical and operationally‐simple Pd(II)−phosphine precatalysts in the emerging amide bond cross‐coupling manifold. The reactions are efficient at 0.10 mol% loading, furnishing biaryl ketones with high chemoselectivity for N−C(O) bond cleavage. This versatile method enables for the first time to achieve Pd−phosphine‐catalyzed cross‐coupling of amides at ppm loading. This C−N cross‐coupling can be used to efficiently furnish pharmaceutical intermediates by orthogonal Pd‐catalyzed cross‐couplings. We fully expect that operationally‐simple [(PR3)2Pd(II)X2] precatalysts as effective triggers for N−C(O) cross‐coupling will be of broad synthetic and catalytic interest. magnified image
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Phosphine-catalyzed activation of cyclopropenones: a versatile C 3 synthon for (3+2) annulations with unsaturated electrophiles
We herein report a phosphine-catalyzed (3 + 2) annulation of cyclopropenones with a wide variety of electrophilic π systems, including aldehydes, ketoesters, imines, isocyanates, and carbodiimides, offering products of butenolides, butyrolactams, maleimides, and iminomaleimides, respectively, in high yields with broad substrate scope. An α-ketenyl phosphorous ylide is validated as the key intermediate, which undergoes preferential catalytic cyclization with aldehydes rather than stoichiometric Wittig olefinations. This phosphine-catalyzed activation of cyclopropenones thus supplies a versatile C 3 synthon for formal cycloadditon reactions.
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- PAR ID:
- 10412556
- Date Published:
- Journal Name:
- Chemical Science
- Volume:
- 13
- Issue:
- 43
- ISSN:
- 2041-6520
- Page Range / eLocation ID:
- 12769 to 12775
- 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/D2SC04092A
