Regioselective Electrophilic Addition to Propargylic B(MIDA)s Enabled by β‐Boron Effect
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Published:2023-08-26
Issue:30
Volume:10
Page:
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ISSN:2198-3844
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Container-title:Advanced Science
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language:en
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Short-container-title:Advanced Science
Author:
Li Yin1,
Chen Zhi‐Hao1,
Lin Shuang1,
Liu Yuan1,
Qian Jiasheng1,
Li Qingjiang1,
Huang Zhi‐Shu1,
Wang Honggen1ORCID
Affiliation:
1. Guangdong Key Laboratory of Chiral Molecule and Drug Discovery School of Pharmaceutical Sciences Sun Yat‐Sen University Guangzhou 510006 China
Abstract
AbstractElectrophilic addition reaction to alkynes is of fundamental importance in organic chemistry, yet the regiocontrol when reacting with unsymmetrical 1,2‐dialkyl substituted alkynes is often problematic. Herein, it is demonstrated that the rarely recognized β‐boron effect can confer a high level of site‐selectivity in several alkyne electrophilic addition reactions. A broad range of highly functionalized and complex organoborons are thus formed under simple reaction conditions starting from propargylic MIDA (N‐methyliminodiacetic acid) boronates. These products are demonstrated to be valuable building blocks in organic synthesis. In addition to the regiocontrol, this study also observes a drastic rate enhancement upon B(MIDA) substitution. Theoretical calculation reveals that the highest occupied molecular obital (HOMO) energy level of propargylic B(MIDA) is significantly raised by 0.3 eV, and the preferential electrophilic addition to the γ position is due to its higher HOMO orbital coefficient and more negative natural bond orbital (NBO) charge compared to the β position. This study demonstrates the potential of utilizing the β‐boron effect in stereoelectronic control of chemical transformations, which can inspire further research in this area.
Funder
National Natural Science Foundation of China
Subject
General Physics and Astronomy,General Engineering,Biochemistry, Genetics and Molecular Biology (miscellaneous),General Materials Science,General Chemical Engineering,Medicine (miscellaneous)