1,2-Bis-boronic esters are versatile intermediates that enable the rapid elaboration of simple alkene precursors. Previous reports on their selective mono-functionalization have targeted the most accessible position, retaining the more hindered secondary boronic ester. In contrast, we have found that photoredox-catalyzed mono-deboronation generates primary β-boryl radicals that undergo rapid 1,2-boron shift to form thermodynamically favored secondary radicals, allowing for selective transformation of the more hindered boronic ester. The pivotal 1,2-boron shift, which has been demonstrated to be stereoretentive, enables access to a wide range of functionalized boronic esters and has been applied to highly diastereoselective fragmentation and transannular cyclization reactions. Furthermore, its generality has been shown in a radical cascade reaction with an allylboronic ester.

1,2-Boron Shifts of β-Boryl Radicals Generated from Bis-boronic Esters Using Photoredox Catalysis / D. Kaiser, A. Noble, V. Fasano, V.K. Aggarwal. - In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. - ISSN 0002-7863. - 141:36(2019 Sep 11), pp. 14104-14109. [10.1021/jacs.9b07564]

1,2-Boron Shifts of β-Boryl Radicals Generated from Bis-boronic Esters Using Photoredox Catalysis

V. Fasano
Penultimo
;
2019

Abstract

1,2-Bis-boronic esters are versatile intermediates that enable the rapid elaboration of simple alkene precursors. Previous reports on their selective mono-functionalization have targeted the most accessible position, retaining the more hindered secondary boronic ester. In contrast, we have found that photoredox-catalyzed mono-deboronation generates primary β-boryl radicals that undergo rapid 1,2-boron shift to form thermodynamically favored secondary radicals, allowing for selective transformation of the more hindered boronic ester. The pivotal 1,2-boron shift, which has been demonstrated to be stereoretentive, enables access to a wide range of functionalized boronic esters and has been applied to highly diastereoselective fragmentation and transannular cyclization reactions. Furthermore, its generality has been shown in a radical cascade reaction with an allylboronic ester.
Settore CHIM/06 - Chimica Organica
11-set-2019
28-ago-2019
Article (author)
File in questo prodotto:
File Dimensione Formato  
jacs.9b07564.pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 1.48 MB
Formato Adobe PDF
1.48 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/952285
Citazioni
  • ???jsp.display-item.citation.pmc??? 18
  • Scopus 69
  • ???jsp.display-item.citation.isi??? 70
social impact