C−Boron Enolates Enable Palladium Catalyzed Carboboration of Internal 1,3‐Enynes

• Published in: Angewandte Chemie International Edition Vol. 60; no. 39; pp. 21231 - 21236
• Main Authors: Wang, Ziyong, Wu, Jason, Lamine, Walid, Li, Bo, Sotiropoulos, Jean‐Marc, Chrostowska, Anna, Miqueu, Karinne, Liu, Shih‐Yuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20-09-2021; Wiley-VCH Verlag
• Edition: International ed. in English
• Subjects: Acetals; Alkynes; azaborine; Boron; carboboration; Chemical Sciences; Coordination compounds; C−boron enolates; enyne; Nucleophiles; Palladium; Stereoselectivity; Substrates; azaborine · carboboration · C-boron enolates · enyne · palladium
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202108534

A new family of carbon‐bound boron enolates, generated by a kinetically controlled halogen exchange between chlorocatecholborane and silylketene acetals, is described. These C−boron enolates are demonstrated to activate 1,3‐enyne substrates in the presence of a Pd0/Senphos ligand complex, resulting in the first examples of a carboboration reaction of an alkyne with enolate‐equivalent nucleophiles. Highly substituted dienyl boron building blocks are produced in excellent site‐, regio‐, and diastereoselectivity by the described catalytic cis‐carboboration reaction.
A new family of carbon‐bound boron enolates, in cooperation with a Pd complex supported by an 1,4‐azaborine‐derived phosphine ligand, transforms enynes into highly substituted dienyl boronates in exquisite site‐, regio‐, and cis‐diastereoselectivity.