Inversion or retention? Effects of acidic additives on the stereochemical course in enantiospecific suzuki-miyaura coupling of α-(acetylamino) benzylboronic esters
The stereochemical course of the stereospecific Suzuki-Miyaura coupling of enantioenriched α-(acetylamino)benzylboronic esters with aryl bromides can be switched by the choice of acidic additives in the presence of a Pd/XPhos catalyst system. Highly enant
Bis-sulfamyl imines: Potent substrates for asymmetric additions of arylboroxines under rhodium catalysis
Bis-sulfamyl imines are shown to be potentially ideal substrates for rhodium-catalysed asymmetric additions of arylboron nucleophiles as they show: (i) near perfect enantioselectivities (11 examples, 98-99+% ee), (ii) good to excellent diastereoselectivities (10-32:1 rac:meso), and (iii) high functional group tolerance in removal of the low molecular weight protecting group via mild heating in aqueous pyridine.
Crampton, Rosemary,Woodward, Simon,Fox, Martin
p. 903 - 906
(2011/06/19)
Stereospecific Suzuki-Miyaura coupling of chiral α-(Acylamino) benzylboronic esters with inversion of configuration
The first invertive B-alkyl Suzuki-Miyaura coupling has been achieved. The coupling of enantioenriched α-(acylamino)benzylboronic esters with aryl bromides and chlorides took place efficiently in toluene at 80 °C in the presence of Pd(dba)2 (5 mol %), XPhos (10 mol %), K 2CO3 (3 equiv), and H2O (2 equiv). The reaction proceeded with inversion of configuration to give diarylmethanamine derivatives in high yields with high conservation of enantiomeric excesses.