Author, as appears in the article.: Ricart, J. M. ; García-López, D.; Civit, M.; Vogels, C. ; Westcott, S. ; Fernández, E. ; Carbó, J.

Department: Química Física i Inorgànica

URV's Author/s: RICART PLA, JOSE MANUEL; García-López, D.; Civit, M.; Vogels, C. ; Westcott, S. ; FERNÁNDEZ GUTIÉRREZ, MARIA ELENA; CARBÓ MARTIN, JORGE JUAN

Keywords: selenoboration stereoselective anti-addition

Abstract: The stereoselective anti-addition of selenoboranes to α,β-acetylenic esters and amides was achieved in a transition metal-free context using catalytic amounts of PCy3. The reaction provides anti-3,4- selenoboration with concomitant delivery of α-vinyl selenides by protodeboronation with MeOH. Interestingly, in the absence of phosphine the selenoboration switches towards the formation of β-vinyl selenides. Theoretical calculations rationalize the regio- and stereoselectivity of the reaction by discovering a new mechanism for the anti-3,4-selenoboration. While the selenoborane is activated via the “push–pull” effect of B, the phosphine interacts with the β position of the alkynoate switching the polarity of the triple bond and favoring 1,3-selenoboration which provides the α-addition of the selenyl group. Then, the autocatalytic action of a second selenoborane reagent, which coordinates to the phosphorus ylide intermediate, determines the stereoselectivity and completes the catalytic process. Finally, the comparison of selenoborane reagents with diboranes and silaboranes, which have exhibited analogous reactivity, shows that the selenium moiety has a larger nucleophilic character favoring the performance of the reaction under mild conditions.

Research group: Química Quàntica

Thematic Areas: Química Química Chemistry

licence for use: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 2044-4753

Author identifier: 0000-0002-2610-5535; ; ; ; ; 0000-0001-9025-1791; 0000-0002-3945-6721

Record's date: 2019-01-25

Last page: 3628

Journal volume: 8

Papper version: info:eu-repo/semantics/publishedVersion

Link to the original source: https://pubs.rsc.org/en/content/articlelanding/2018/CY/C7CY02295F#!divAbstract

Funding program: plan; Excelencia; CTQ2016-80328-P plan; Excelencia; CTQ2014-52774-P altres; Grupos consolidados; 2014SGR199

Article's DOI: 10.1039/c7cy02295f

Entity: Universitat Rovira i Virgili

Journal publication year: 2018

First page: 3617

Publication Type: Article Artículo Article