Metal-free borylative dearomatization of indoles: exploring the divergent reactivity of aminoborane C-H borylation catalysts.
Chem Sci
; 9(22): 5057-5063, 2018 Jun 14.
Article
de En
| MEDLINE
| ID: mdl-29938036
ABSTRACT
While the dearomatization of indoles by carbon-boron bond forming reactions is new and quite promising, they are so far mainly metal-catalyzed. Here, we establish the use of metal-free catalysts in promoting such reactions in an atom-efficient way. The in situ generated ambiphilic aminoborane catalyst (1-Pip-2-BH2-C6H4)2 (Pip = piperidyl) promotes borylative dearomatization of various 1-arylsulfonyl indoles with pinacolborane in a syn addition fashion, with H and Bpin groups added respectively to the 2 and 3 positions of indoles. Catalysis proceeds with good to excellent conversion and essentially with complete regio- and diastereoselectivity. From mechanistic insights and DFT computations, we realized and established that prototypical boranes can also catalyze this borylative dearomatization.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Chem Sci
Année:
2018
Type de document:
Article