Breaking Conventional Site Selectivity in C-H Bond Activation: Selective sp3versus sp2Silylation by a Pincer-Based Pocket

Qin，Chuan1; Huang，Zhidao1; Wu，Song Bai2,3; Li，Zhuangxing1; Yang，Yuhong2; Xu，Songgen1; Zhang，Xin1; Liu，Guixia1; Wu，Yun Dong3; Chung，Lung Wa2; Huang，Zheng1

2022

10.1021/jacs.2c09356

Journal of the American Chemical Society   Impact Factor & Quartile

0002-7863

1520-5126

A deeply ingrained assumption in the conventional understanding and practice of organometallic chemistry is that an unactivated aliphatic C(sp3)-H bond is less reactive than an aromatic C(sp2)-H bond within the same molecule given that they are at positions unbiasedly accessible for activation. Herein, we demonstrate that a pincer-ligated iridium complex catalyzes intramolecular dehydrogenative silylation of the unactivated δ-C(sp3)-H (δto the Si atom) with exclusive site selectivity over typically more reactive ortho δ-C(sp2)-H bonds. A variety of tertiary hydrosilanes undergo δ-C(sp3)-H silylation to form 5-membered silolanes, including chiral silolanes, which can undergo further oxidation to produce enantiopure β-aryl-substituted 1,4-diols. Combined computational and experimental studies reveal that the silylation occurs via the Si-H addition to a 14-electron Ir(I) fragment to give an Ir(III) silyl hydride complex, which then activates the C(sp3)-H bond to form a 7-coordinate, 18-electron Ir(V) dihydride silyl intermediate, followed by sequential reductive elimination of H2 and silolane. The unprecedented site selectivity is governed by the distortion energy difference between the rate-determining δ-C(sp3)-H and δ-C(sp2)-H activation, although the activation at sp2 sites is much more favorable than sp3 sites by the interaction energy.

SCI

English

NI Journal Papers

Corresponding

National Key R&D Program of China["2021YFA1501700","2021YFA1500100"] ; National Natural Science Foundation of China["21825109","21821002","21732006","22072178","21933003","22193020","22193023"] ; Shenzhen Nobel Prize Scientists Laboratory Project[C17783101] ; Guangdong Provincial Key Laboratory of Catalytic Chemistry[2020B121201002]

Chemistry

Chemistry, Multidisciplinary

WOS:000883936900001

AMER CHEMICAL SOC

2-s2.0-85141707128

Scopus

1.The State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry,University of Chinese Academy of Sciences,Chinese Academy of Sciences,Shanghai,345 Lingling Road,200032,China
2.Shenzhen Grubbs Institute,Department of Chemistry,Guangdong Provincial Key Laboratory of Catalysis,Southern University of Science and Technology,Shenzhen,518055,China
3.Lab of Computational Chemistry and Drug Design,Laboratory of Chemical Genomics,Peking University Shenzhen Graduate School,Shenzhen,518055,China

Qin，Chuan,Huang，Zhidao,Wu，Song Bai,et al. Breaking Conventional Site Selectivity in C-H Bond Activation: Selective sp3versus sp2Silylation by a Pincer-Based Pocket[J]. Journal of the American Chemical Society,2022.

Qin，Chuan.,Huang，Zhidao.,Wu，Song Bai.,Li，Zhuangxing.,Yang，Yuhong.,...&Huang，Zheng.(2022).Breaking Conventional Site Selectivity in C-H Bond Activation: Selective sp3versus sp2Silylation by a Pincer-Based Pocket.Journal of the American Chemical Society.

Qin，Chuan,et al."Breaking Conventional Site Selectivity in C-H Bond Activation: Selective sp3versus sp2Silylation by a Pincer-Based Pocket".Journal of the American Chemical Society (2022).