4222-13-3

Upstream product

• 3780-21-0 2,2-diphenylchroman-4-one 
• 119-61-9 benzophenone 
• 118-93-4 o-hydroxyacetophenone 
• 4222-11-1 4-acetoxy-2,2-diphenylbenzopyran 
• 35817-28-8 4-phenoxy-2H-1-benzopyran-2-one 
• 343309-52-4 2-(3-hydroxy-3,3-diphenylprop-1-yn-1-yl)phenol 
• 3923-52-2 1,1-diphenyl-2-propyn-1-ol 
• 184368-89-6 1-iodo-2-(tert-butyldimethylsilyloxy)benzene 
• 104-15-4 toluene-4-sulfonic acid 

Downstream Products

• 3780-21-0 2,2-diphenylchroman-4-one 
• 4222-11-1 4-acetoxy-2,2-diphenylbenzopyran 
• 4970-20-1 2,2-diphenyl-chroman-3,4-dione 

Relevant academic research and scientific papers

Acid-promoted cyclization of 2-propynolphenols leading to 4-tosyloxy-2H-chromenes

A novel and efficient p-TsOH-promoted cascade cyclization of 2-propynolphenols is developed to give 4-tosyloxy-2H-chromenes in moderate to efficient yields. It is noted that p-TsOH acts not only as a promoter in this reaction, and also as the sulfonate source. Importantly, the obtained 4-tosyloxy-2H-chromenes can be used as versatile intermediates for the synthesis of various functionalized compounds through diverse metal-catalyzed cross-coupling reactions. Moreover, this method can be enlarged to gram scale.

BF3·Et2O-promoted cleavage of the Csp-Csp2 bond of 2-propynolphenols/anilines: Route to C2-alkenylated benzoxazoles and benzimidazoles

A novel BF3·Et2O-promoted tandem reaction of easily prepared 2-propynolphenols/anilines and trimethylsilyl azide is developed to give C2-alkenylated benzoxazoles and benzimidazoles in moderate to good yields. Most reactions could be accomplished in 30 min at room temperature. This tandem process involves a Csp-Csp2 bond cleavage and a C-N bond formation. Moreover, both tertiary and secondary propargylic alcohols with diverse functional groups were tolerated under the mild conditions.

Convenient and highly efficient routes to 2 H-chromene and 4-chromanone derivatives: Iodine-promoted and p-toluenesulfonic acid catalyzed cascade cyclizations of propynols

A convenient strategy is presented for the easy preparation of a series of 2 H-chromenes under mild conditions through iodocyclization of readily accessible propynols. In addition, various 4-chromanones can be synthesized through a p-toluenesulfonic acid catalyzed cascade cyclization with high efficiency (yields up to 99%). Our developed reaction systems are proven to have good functional-group applicability and can be scaled up to gram quantities in satisfactory yields. These systems also provide a new synthetic strategy for two types of important flavonoid skeleton without using costly and toxic metal catalysts. Additionally, the resulting halides could be further exploited in subsequent palladium-catalyzed coupling reactions, so these compounds could act as potential intermediates for the construction of some valuable drug molecules.

Some Phenoxy-2H-benzo[b]pyrans

Successful methods have been developed for the syntheses of 6-, 7- and 8-phenoxy-2H-benzo-[b]pyrans, 4-,5-,6-,7- and 8-phenoxy-2,2-dimethyl-2H-benzo[b]pyrans and 4- and 7-phenoxy-2,2-diphenyl-2H-benzo[b]pyrans.

Electron Transfer Oxidation of Enol Derivatives of 2,3-Dihydrobenzopyran-4-ones

Dihydrobenzopyrones 1a-c and their enol acetates 3a-c have been submitted to oxidation under single electron transfer (SET) conditions, using three alternative ways of activation: chemical oxidation with cerium(IV) ammonium nitrate (CAN), photochemical oxidation using triphenylpyrylium tetrafluoroborate (TPT) as sensitizer or electrochemical oxidation.The most significant products obtained are diketones 4, hydroxyketones 5, rearranged benzopyrones 6, enones 9 and, in the case of enol acetate 3c, 2-methylchromone (10) and 1,2-diphenylethane (13).These results are rationalized according to three major pathways from the radical cations: i) formation of the α-carbonyl radicals I (trough deprotonation of the enols 2(+). or cleavage of the carbonyl-oxygen bond of their acetates 3(+).), eventually followed by secondary oxidation to the carbenium ions II, ii) breaking of the bond linking C2 with one of the substituents and iii) ring opening.