Catalytic methods of creation and functionalization of the coumarin skeleton

Synthesis of 3-methoxy-6-phenyl-6, 6a-dihydro-[1] benzopyrano- [3, 4-b] [1] benzopyran.

“…This result is conform to others described in the literature [23]. Howover, Federov and al showed that the intramolecular hydroarylation can be obtained in higher yield (60-91%) using catalytic amount of Pd(OAc) 2 [24].…”

“…4-(2-hydroxyphenylcarbonyl)-7-methoxy-1-phenylbenzopyran 5 was isolated after purification with 23% yield. The use of another electrodonor group insensitive to the action of BCl 3 in place of methoxy group of position 3 will allow the reaction to give better yields [24].…”

Zeolite‐promoted Synthesis of Coumarins and Thiocoumarins

“…This variety of properties has led to numerous syntheses via very different routes . Among them, the Lewis acid‐promoted cyclization of aryl propiolates is one of the most simple and convergent methods (Scheme , top arrow) . This strategy also offers a large and useful modularity, as the aryl, the propiolate substituent as well as the linkage nature could easily be tuned towards specific properties.…”

Noncovalent Catalysis for Enantioselective Direct Aldol Reaction of 3‐Acetylcoumarins to Pyrazole‐4,5‐diones

“…[9] Enantioselective synthesis and functionalization of chromene containing compounds have thereby drawn much attention from the synthetic chemistry community. [10] While contemplating enantioselective direct aldol reactions of unactivated ketones through noncovalent catalysis, we realized that 3-acetyl-2H-chromen-2-ones (3-acetylcoumarins) are a class of unactivated ketones for which enamine formation is unfavourable. Possibly because of this reason, 3-acetylcoumarins have rarely been applied in catalytic enantioselective transformations.…”