Ru II ‐Catalyzed Regioselective Debrominative Annulation Reaction of Salicylaldehydes and Propargyl Bromide: Synthesis of 2‐Methylchromones

Access to Chiral Chromenones through Organocatalyzed Mannich/Annulation Sequence

Herein we report an efficient and practical method to access chiral chromenones bearing one α-amino stereogenic center in the β position of the carbonyl group. The quinine-derived squaramide could efficiently promote Mannich/cycloketalization/dehydration tandem reactions between 1-(2-hydroxyaryl)-1,3-diketones and functionalized imines generated in situ, providing a wide range of chiral chromenones with propargylamine or α-amino ester moieties with good results (54 examples, up to 98% ee).

Synthesis of 3-(2-quinolyl) chromones from ynones and quinoline N-oxides via tandem reactions under transition metal- and additive-free conditions

The synthesis of 3-(2-quinolyl) chromones from ynones and quinoline N-oxides via a sequential [3+2] cycloaddition/ring-opening/O-arylation reaction under transition metal- and additive-free conditions is reported.