A General Method to Access Sterically Encumbered Geminal Bis(boronates) via Formal Umpolung Transformation of Terminal Diboron Compounds

• Published in: Angewandte Chemie International Edition Vol. 63; no. 4; pp. e202315232 - n/a
• Main Authors: Ning, Peng‐Fei, Wei, Yi, Chen, Xin‐Yi, Yang, Yi‐Fei, Gao, Feng‐Chen, Hong, Kai
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 22.01.2024; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Chemistry; Chemistry, Multidisciplinary; Construction; Diborylalkanes; Functional groups; Geminal Bis(Boronates); Nucleophiles; Organoboron; Physical Sciences; Science & Technology; Steric hindrance; Synthetic Methods; Umpolung Transformation; GEM-DIBORYLALKANES; 1,1-DIBORONATE ESTERS; Umpolung Transformation; Geminal Bis(Boronates); SECONDARY; N-OXIDES; ALKYL-HALIDES; TERTIARY BORONIC ESTERS; CATALYZED DIBORYLATION; Synthetic Methods; Organoboron; DIASTEREOSELECTIVE SYNTHESIS; ALPHA-BORYL CARBANIONS; Diborylalkanes; BENZYLIC BORYLATION
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202315232

General methods for the preparation of geminal bis(boronates) are of great interest due to their widespread applications in organic synthesis. While the terminal gem‐diboron compounds are readily accessible, the construction of the sterically encumbered, internal analogues has remained a prominent challenge. Herein, we report a formal umpolung strategy to access these valuable building blocks. The readily available 1,1‐diborylalkanes were first converted into the corresponding α‐halogenated derivatives, which then serve as electrophilic components, undergoing a formal substitution with a diverse array of nucleophiles to form a series of C−C, C−O, C−S, and C−N bonds. This protocol features good tolerance to steric hindrance and a wide variety of functional groups and heterocycles. Notably, this strategy can also be extended to the synthesis of diaryl and terminal gem‐diboron compounds, therefore providing a general approach to various types of geminal bis(boronates). A general method for accessing sterically encumbered geminal bis(boronates) was developed based on a formal umpolung strategy. The polarity inversion of the readily available 1,1‐diborylalkanes allows their corresponding α‐halogenated derivatives to undergo a formal substitution with a wide variety of nucleophiles to form C−C, C−O, C−S, and C−N bonds, featuring excellent tolerance to steric hindrance and functional groups.