Convenient asymmetric synthesis of both enantiomers of 3,4-disubstituted 3,4-dihydro-1,4-benzoxazin-2-ones

Efficient access to chiral dihydrobenzoxazinones via Rh-catalyzed hydrogenation

“…Therefore, enormous efforts were made to the development of efficient enantioselective methods, and some asymmetric synthetic methodologies have been established to access chiral dihydrobenzoxazinones and derivatives over the past decades. [5][6][7][8][9][10][11] The asymmetric catalytic reduction of prochiral benzoxazinones and derivatives is one of the most important methods, 5-7 including asymmetric hydrosilylation, 5 asymmetric transfer hydrogenation, 6 and asymmetric hydrogenation. 3b,7 In addition, other efficient enantioselective methods were involved to prepare chiral dihydrobenzoxazinones and derivatives, 4b,8-11 such as addition reaction of indoles or pyrroles with benzoxazinones, 8 Rhcatalyzed asymmetric arylation of benzoxazinones and quinoxalinones with arylboroxines, 4b dynamic kinetic resolution of a-bromo arylacetates in nucleophilic substitution with N-alkylated 2-aminophenols, 9 asymmetric Mannich reaction of ketones with benzoxazinones, 10 and organocatalytic reductive amination.…”

“…[5][6][7][8][9][10][11] The asymmetric catalytic reduction of prochiral benzoxazinones and derivatives is one of the most important methods, 5-7 including asymmetric hydrosilylation, 5 asymmetric transfer hydrogenation, 6 and asymmetric hydrogenation. 3b,7 In addition, other efficient enantioselective methods were involved to prepare chiral dihydrobenzoxazinones and derivatives, 4b,8-11 such as addition reaction of indoles or pyrroles with benzoxazinones, 8 Rhcatalyzed asymmetric arylation of benzoxazinones and quinoxalinones with arylboroxines, 4b dynamic kinetic resolution of a-bromo arylacetates in nucleophilic substitution with N-alkylated 2-aminophenols, 9 asymmetric Mannich reaction of ketones with benzoxazinones, 10 and organocatalytic reductive amination. 11 Transition-metal-catalyzed asymmetric hydrogenation has been regarded as a straightforward and efficient method for the synthesis of chiral compounds with high atom-economic advantage.…”