Atom‐Efficient Synthesis of Alkynylfluoroborates Using BF3‐Based Frustrated Lewis Pairs. Issue 45 (6th October 2016)

• Record Type: Journal Article
• Authors: Iashin, Vladimir; Chernichenko, Konstantin; Pápai, Imre; Repo, Timo
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 45(2016)
• Page Start: 14146
• Page End: 14150
• Publication Date: 2016-10-06
• Subjects: alkynes -- amines -- boron trifluoride -- C−H activation -- frustrated Lewis pairs; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201608520
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A sterically demanding amine, 1, 2, 2, 6, 6‐pentamethylpiperidine (PMP), forms a highly reactive Lewis acid–base pair with boron trifluoride. This pair reacts with terminal acetylenes to give the products of C(sp)−H borylation, previously unknown tri‐ and tetraalkynylboron compounds. Trialkynylfluoroborates can serve as surrogates of alkynyltrifluoroborates for C−C coupling reactions. Using aqueous NaOH, PMP can be recovered from its tetrafluoroborate salt, which is formed as a C−H borylation byproduct. Combining the discovered borylation reactivity with the PMP recovery provides a straightforward and atom‐efficient approach to synthetically useful alkynylfluoroborates. Abstract : C−H borylation : A simple aliphatic amine and BF3 complexes react with terminal acetylenes to give the C(sp)−H borylation products, previously unknown tri‐ and tetraalkynylboron derivatives. The amine, which is converted into the tetrafluoroborate salt during borylation, can be recovered by using aqueous NaOH.