Cp*Co(III)/MPAA-Catalyzed Enantioselective Amidation of Ferrocenes Directed by Thioamides under Mild Conditions

Liu, Yanhua; Li, Pengxiang; Yao, Qi‐Jun; Zhang, Zhuo‐Zhuo; Huang, Dan-Ying; Le, Minh; Song, Hong; Liu, Lei; Shi, Bing‐Feng

doi:10.1021/acs.orglett.9b00511

Cited by 166 publications

(68 citation statements)

References 82 publications

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“…It is noteworthy that the enantioselective CÀHf unctionalization of ferrocene derivatives remains challenging with 3d metal catalysts,a ss imilar moderate enantioselectivities have been obtained by Shi et al as well (Scheme 22). [59] In contrast, the use of achiral oxazoline as the directing group [72] allowed for the iron-catalyzed arylation ferrocene derivatives 88 to provide the planar-chiral products in > 99 %d iastereoselectivity but moderate yield. [71] Employing the same class of substrates,acopper-catalyzed diastereoselective thiolation of ferrocenamides was later disclosed by Yu et al [73] In contrast, Ackermannsg roup established ah ighly enantioselective iron-catalyzed C À Ha ctivation of (aza)indoles [74] (Scheme 27).…”

Section: Methodsmentioning

confidence: 99%

Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

et al. 2019

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Molecular syntheses largely rely on time‐ and labour‐intensive prefunctionalization strategies. In contrast, C−H activation represents an increasingly powerful approach that avoids lengthy syntheses of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, and crop protection, among others. The enantioselective functionalization of omnipresent C−H bonds has emerged as a transformative tool for the step‐ and atom‐economical generation of chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium and rhodium catalysts. Indeed, despite significant achievements, the use of inexpensive and sustainable 3d metals in asymmetric C−H activations is still clearly in its infancy. Herein, we discuss the remarkable recent progress in enantioselective transformations via organometallic C−H activation by 3d base metals up to April 2019.

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Section: Methodsmentioning

confidence: 99%

Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

et al. 2019

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“…The target product 9 was obtained in good yield and moderate enantioselectivity (73 %, 82:18 er). To expanding the scope of the CCA‐enabled enantioselective C−H activation reactions, we aimed to further develop CCAs with axial chirality. Although axially chiral biaryl‐type CCAs ( L1 – L4 ) gave poor enantiocontrol (48:52 to 29:71 er), the newly developed axially chiral styrene‐type CCA 4 dl gave better enantioselectivity (82:18 er), thus indicating that these novel styrene atropisomers might open up new avenues in asymmetric synthesis.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Axially Chiral Styrenes through Pd‐Catalyzed Asymmetric C−H Olefination Enabled by an Amino Amide Transient Directing Group

Song

Yao

et al. 2020

Angewandte Chemie

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The atroposelective synthesis of axially chiral styrenes remains a formidable challenge due to their relatively lower rotational barriers compared to the biaryl atropoisomers. Herein, we describe the construction of axially chiral styrenes through PdII‐catalyzed atroposelective C−H olefination, using a bulky amino amide as a transient chiral auxiliary. Various axially chiral styrenes were produced with good yields and high enantioselectivity (up to 95 % yield and 99 % ee). Carboxylic acid derivatives of the resulting axially chiral styrenes showed superior enantiocontrol over the biaryl counterparts in CoIII‐catalyzed enantioselective C(sp3)−H amidation of thioamide. Mechanistic studies suggest that C−H cleavage is the enantioselectivity‐determining step.

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“…We realized dehydrogenative annulation, and highly enantioselective olefination and acylation of N, N‐dimethylaminomethyl ferrocene in the absence of external oxidant . So far, significant advancements on transition metal‐catalyzed oxidative coupling of ferrocene derivatives have been accomplished using ferrocenylamides, 2‐pyridine, 1‐isoquinoline, ketone, thione, thioamide and oxazoline derivatives as substrates. However, ferrocenyl carboxylic acid as starting material has rarely been studied .…”

Section: Figurementioning

confidence: 99%