Intramolecular Activation of C-O Bond by an o-Boryl Group in o-(Alkoxysilyl)(diarylboryl)benzenes

Tomomi Shimizu; Shogo Morisako; Yohsuke Yamamoto; Atsushi Kawachi

doi:10.1021/acsomega.9b03784

Intramolecular Activation of C-O Bond by an o-Boryl Group in o-(Alkoxysilyl)(diarylboryl)benzenes

ACS Omega. 2019 Dec 30;5(1):871-876. doi: 10.1021/acsomega.9b03784. eCollection 2020 Jan 14.

Authors

Tomomi Shimizu¹, Shogo Morisako², Yohsuke Yamamoto², Atsushi Kawachi¹

Affiliations

¹ Department of Applied Chemistry, Graduate School of Science and Engineering and Department of Chemical Science and Technology, Faculty of Bioscience and Applied Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584, Japan.
² Department of Chemistry, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.

Abstract

Halogen-lithium exchange reaction of o-(silyl)bromobenzene 5 with tert-BuLi afforded o-(silyl)lithiobenzene 6, which was reacted with (alkoxy)diarylboranes 7 to form borate intermediates 8. Treatment of 8 with chlorotrimethylsilane formed o-(alkoxysilyl)(diarylboryl)benzenes 4. The C-O bond in 4 was activated by intramolecular interaction between the oxygen atom and the boron atom. 4a readily reacted with MeOH and EtOH to afford the corresponding alkoxysilanes 10 and 11, respectively. Treatment of 10 with 1,4-diazabicyclo[2.2.2]octane (DABCO) afforded the silyloxyborate complex 13.