Catalytic enantioselective synthesis of chiral tetraarylmethanes

Li, Xingguang; Duan, Meng; Deng, Zhiqin; Shao, Qianzhen; Chen, Min; Zhu, Guangyu; Houk, K. N.; Sun, Jianwei

doi:10.1038/s41929-020-00535-4

Cited by 74 publications

(34 citation statements)

References 50 publications

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Section: Introductionmentioning

confidence: 99%

“…Indole-based imine methides have been demonstrated to be versatile intermediates in a range of organocatalytic asymmemtric transformations, particularly in 1,4- or 1,6-conjugate addition 22 – 29 and cycloaddition 30 – 34 , leading to diverse enantioenriched indole derivatives 35 – 38 . Among them, we have reported an asymmetric 1,6-conjugate addition of such intermediates for the synthesis of chiral tetraarylmethanes containing an indole unit 29 . Recently, Antilla’s group and our group have developed remote asymmetric 1,8-addition to such species with chiral phosphoric acid (CPA) catalysis, providing efficient access to enantioenriched triarylmethanes and allenes, respectively 39 , 40 .…”

Section: Introductionmentioning

confidence: 99%

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Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides

Duan

et al. 2021

Nat Commun

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Catalytic asymmetric dearomatization (CADA) is a powerful tool for the rapid construction of diverse chiral cyclic molecules from cheap and easily available arenes. This work reports an organocatalytic enantioselective dearomatization of substituted thiophenes in the context of a rare remote asymmetric 1,10-conjugate addition. By suitable stabilization of the thiophenyl carbocation with an indole motif in the form of indole imine methide, excellent remote chemo-, regio-, and stereocontrol in the nucleophilic addition can be achieved with chiral phosphoric acid catalysis under mild conditions. This protocol can be successfully extended to the asymmetric dearomatization of other heteroarenes including selenophenes and furans. Control experiments and DFT calculations demonstrate a possible pathway in which hydrogen bonding plays an important role in selectivity control.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides

Duan

et al. 2021

Nat Commun

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“… 5–8 Indeed, even racemic or achiral syntheses of tetraarylmethanes have been an elusive topic of investigation in organic synthesis. 6 In this context and in continuation of our effort in the studies of asymmetric reactions of para -quinone methides ( p -QMs) 9,10 as well as the synthesis of chiral tetraarylmethanes, 8 we envisioned that suitable oxidation of racemic triarylmethane 1 is expected to generate triarylmethyl cation IM1 ( Scheme 1c ). With one aryl group as para -hydroxyphenyl, this cation could be stabilized in the form of p -QM IM2 .…”

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confidence: 99%

“…These results suggested that it is the hydrogen bonding interaction with the ortho -directing group, not the steric or electronic effect, that leads to the excellent enantiocontrol in the standard protocol. 8 …”

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confidence: 99%

Organocatalytic asymmetric formal oxidative coupling for the construction of all-aryl quaternary stereocenters

et al. 2021

Chem. Sci.

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“…Mechanistically, achieving such enantioconvergent transformations necessitates the removal of chirality from the substrate, which is typically realized by the formation of achiral ionic intermediates. The classical nucleophilic substitution approach 3 , which requires the generation of stabilized carbocation/carbanion intermediates for effective chirality control, is limited to the specially substituted or activated substrates and not applicable towards the reaction of non-functionalized feedstock materials [4][5][6][7][8][9] .…”

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confidence: 99%

Redox-enabled direct stereoconvergent heteroarylation of simple alcohols

et al. 2021

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The direct transformation of racemic feedstock materials to valuable enantiopure compounds is of significant importance for sustainable chemical synthesis. Toward this goal, the radical mechanism has proven uniquely effective in stereoconvergent carbon-carbon bond forming reactions. Here we report a mechanistically distinct redox-enabled strategy for an efficient enantioconvergent coupling of pyrroles with simple racemic secondary alcohols. In such processes, chirality is removed from the substrate via dehydrogenation and reinstalled in the catalytic reduction of a key stabilized cationic intermediate. This strategy provides significant advantage of utilizing simple pyrroles to react with feedstock alcohols without the need for leaving group incorporation. This overall redox-neutral transformation is also highly economical with no additional reagent nor waste generation other than water. In our studies, oxime-derived iridacycle complexes are introduced, which cooperate with a chiral phosphoric acid to enable heteroarylation of alcohols, accessing a wide range of valuable substituted pyrroles in high yield and enantioselectivity.

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Catalytic enantioselective synthesis of chiral tetraarylmethanes

Cited by 74 publications

References 50 publications

Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides

Organocatalytic enantioselective dearomatization of thiophenes by 1,10-conjugate addition of indole imine methides

Organocatalytic asymmetric formal oxidative coupling for the construction of all-aryl quaternary stereocenters

Redox-enabled direct stereoconvergent heteroarylation of simple alcohols

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