Base-promoted acetal formation with phenyl salicylates

Synthesis of Isocoumarins via Silver(I)-Mediated Annulation of Enol Esters

“…Furthermore, the reaction of the o -iodobenzoic acid with 2-(ethoxy­carbonyl)­vinyl 4-methoxybenzoate ( D ) also produces 2a , albeit in reduced yield (75%). Besides, when enol ester such as E was treated under similar reaction conditions, nucleophilic attack occurs to the aldehyde group of B with the formation of benzodioxanone F . These observations suggest that the enol ester 1a initially reacts with DMAP to produce the enolate (e.g., A which rearranges to B ) along with the intermediate I (Scheme ).…”

6-Oxocyclohexa-2,4-dienylideneketene: A Highly Reactive α-Oxoketene

“…Laser flash photolysis of 1 in CH 3 CN with 308 nm light and time-resolved infrared detection (TRIR) resulted in the irreversible disappearance of the IR band of 1 at 1751 cm -1 and the instantaneous formation of new IR bands at 2135 and 1703 cm -1 , identified as due to the ketene absorption of 2 , and the benzaldehyde carbonyl, respectively (Figure ). The band at 2135 cm -1 disappeared with first-order kinetics (Figure ), even in CH 3 CN freshly distilled from CaH 2 , and this reaction was shown to involve hydration by adventitious H 2 O by the observation of the concurrent growth of the IR absorption of salicylic acid at 1693 cm -1 , and by the observation of a linear dependence on [H 2 O] of the rate of reaction of 2 , which indicated a [H 2 O] of 0.0026 M in the distilled CH 3 CN.…”

Revisiting the Addition of in‐situ Nucleophiles to Allenic Ketones: An Entry Towards Synthesis of Benzodioxins

“…[7] Furthermore, their unique chemical and structural properties create further curiosity. [8] However, methodologies available for the construction of benzodioxin skeletons [9][10][11][12][13][14][15][16] are documented below (Scheme 3).…”