Palladium-Catalyzed Borylative Cyclizations of α-(2-Bromoaryl) Ketones to Form 1,2-Benzoxaborinines

Abstract

Herein, we report that palladium catalyzes the borylative cyclization of α-(2-bromoaryl) ketones to afford 1,2-benzoxaborinines. The developed system is compatible with a variety of functionalities (Me, t-Bu, OMe, NMe 2 , F, Cl, CN, CF 3 , CO 2 Me, and heteroaryl groups) and is applicable to the synthesis of B−O-containing tri-and tetracyclic fusedring compounds.

Recent Expedition in Pd‐ and Rh‐Catalyzed C(Ar)−B Bond Formations and Their Applications in Modern Organic Syntheses

“…This diarylboronic acid enabled the generation of versatile six‐ to nine‐membered π‐extended heteroarenes by an annulative two‐fold Suzuki‐Miyaura process. Recently, Shigeno reported the synthesis of 1,2‐benzoxaborinines through a Pd‐catalyzed borylation of α‐(2‐bromoaryl) ketone and deprotonative intramolecular cyclization (Scheme 6a) [41] …”

“…Recently, Shigeno reported the synthesis of 1,2-benzoxaborinines through a Pd-catalyzed borylation of α-(2-bromoaryl) ketone and deprotonative intramolecular cyclization (Scheme 6a). [41] The synthesis of ArBdan was reported by Li [42] and Majzik/ Fenández [43] by using Pd 2 (dba) 3 /XPhos catalyst system to transfer Bdan to aryl bromides/chlorides from a non-symmetrical diboron reagent B(pin)-B(dan). The reaction was further examined by Song to develop an enantioselective version using Pd(OAc) 2 and L8 catalyst system (Scheme 6b).…”