(o-Phenylenediamino)borylstannanes: Efficient Reagents for Borylation of Various Alkyl Radical Precursors

Kensuke Suzuki; Yoshihiro Nishimoto; Makoto Yasuda

doi:10.1002/chem.202004692

(o-Phenylenediamino)borylstannanes: Efficient Reagents for Borylation of Various Alkyl Radical Precursors

Chemistry. 2021 Feb 24;27(12):3968-3973. doi: 10.1002/chem.202004692. Epub 2020 Dec 29.

Authors

Kensuke Suzuki¹, Yoshihiro Nishimoto^{1

2}, Makoto Yasuda^{1

2}

Affiliations

¹ Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
² Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University Suita, Osaka, 565-0871, Japan.

PMID: 33205553
DOI: 10.1002/chem.202004692

Abstract

(o-Phenylenediamino)borylstannanes were newly synthesized to achieve radical boryl substitutions of a variety of alkyl radical precursors. Dehalogenative, deaminative, decharcogenative, and decarboxylative borylations proceeded in the presence of a radical initiator to give the corresponding organic boron compounds. Radical clock experiments and computational studies have provided insights into the mechanism of the homolytic substitution (S_H 2) of the borylstannanes with alkyl radical intermediates. DFT calculation disclosed that the phenylenediamino structure lowered the LUMO level including the vacant p-orbital on the boron atom to enhance the reactivity to alkyl radicals in S_H 2. Moreover, C(sp³ )-H borylation of THF was accomplished using the triplet state of xanthone.

Keywords: boron; borylstannane; main group elements; radical reactions; tin.