Palladium-Catalyzed Chemoselective Activation of sp<sup>3</sup> vs sp<sup>2</sup> C–H Bonds: Oxidative Coupling To Form Quaternary Centers
作者:Gang Hong、Pradip D. Nahide、Uday Kumar Neelam、Peter Amadeo、Arjun Vijeta、John M. Curto、Charles E. Hendrick、Kelsey F. VanGelder、Marisa C. Kozlowski
DOI:10.1021/acscatal.9b00091
日期:2019.4.5
activation of alkyl C–H bonds vs arene C–H bonds with Pd(OAc)2 has been found to be generalizable to a number of nucleophilic substrates, allowing the formation of a range of hindered quaternary centers. The substrates share a common mechanistic path wherein Pd(II) initiates an oxidative dimerization. The resultant dimer modifies the palladium catalyst to favor activation of alkyl C–H bonds, in contrast to
Cu-Catalyzed Cross-Dehydrogenative Coupling of Heteroaryl C(sp<sup>2</sup>)–H and Tertiary C(sp<sup>3</sup>)–H Bonds for the Construction of All-Carbon Triaryl Quaternary Centers
A Cu-catalyzed protocol for cross-dehydrogenativecoupling of benzofuranones with quinolines, indoles, carbazoles, and thiophene, which furnishes highly functionalized 3,3-diaryl benzofuranones bearing a three aryl quaternary carbon center at the C3 position in good yields, has been developed. A radical mechanism is proposed.
Recyclable nickel-catalyzed C–H/O–H dual functionalization of phenols with mandelic acids for the synthesis of 3-aryl benzofuran-2(3<i>H</i>)-ones under solvent-free conditions
Cooperative catalysis: Green synthesis of 3-aryl benzofuran-2(3H)-ones under solvent-free conditions from phenols and mandelic acids using recyclable Ni(OTf)2 as a catalyst.
Asymmetric Michael Addition Reactions between 3-Substituted Benzofuran-2(3H)-ones and 1,1-Bis(phenylsulfonyl)ethylene Catalyzed by Bifunctional Catalysts Containing Tertiary Amine and Thiourea Groups
Highly enantioselective catalytic conjugate additions of 3-substituted benzofuran-2(3H)-ones to 1,1-bis(phenylsulfonyl)ethylene in the presence of catalysts based on Cinchona alkaloids and containing tertiaryamine and thiourea groups have been developed. Good to excellent stereoselectivities (up to 99 % ee) could be achieved. An interesting effect of substituent positions on stereoselectivities was
I<sub>2</sub>-Mediated Cross-Dehydrogenative Coupling and Amidation of 3-Aryl Benzofuranones with Aryl Amines for the Synthesis of 3,3-Diaryl Indolin-2-ones
We have developed a protocol for efficient synthesis of indolin-2-ones from benzofuranones and arylamines using iodine as a mediator. A diverse range of benzofuranones and arylamines undergo cross-dehydrogenative coupling and amidation of 3-aryl benzofuranones for the cascade reaction to generate products in 24–93% yields. This reaction can be easily scaled-up to give an indolin-2-one in a gram scale