63113-01-9Relevant academic research and scientific papers
Chiral Bicyclic Imidazole-Catalyzed Acylative Dynamic Kinetic Resolution for the Synthesis of Chiral Phthalidyl Esters
Zhou, Muxing,Gridneva, Tatiana,Zhang, Zhenfeng,He, Ende,Liu, Yangang,Zhang, Wanbin
supporting information, p. 1641 - 1645 (2020/11/30)
Utilizing a chiral bicyclic imidazole organocatalyst and adopting a continuous injection process, an alternative route has been developed for the efficient synthesis of chiral phthalidyl ester prodrugs via dynamic kinetic resolution of 3-hydroxyphthalides through enantioselective acylation (up to 99 % ee). The computational studies suggest a general base catalytic mechanism differing from the widely accepted nucleophilic catalytic mechanism. The structure analysis of the key transition states shows that the CH-π interactions and not the previously considered cation/π-π interactions between the catalyst and substrate is the dominant factor giving rise to the observed stereocontrol.
Aromatic Spiranes XXI [1]: Syntheses of Methyl Substituted Phthalaldehydic Acids and their Ethyl and Methyl Esters as Synthones for Syntheses of Methylated 2,2′-Spirobiindandiones
Neudeck
, p. 201 - 217 (2007/10/03)
The isomeric methyl phthalaldehydic acids 11 were obtained from phthalides 4 by bromation (NBS) to the 3-bromo derivatives 7 and subsequent hydrolysis with water. 4 in turn were accessible from dimethyl methyl benzoates 1 by dibromination with NBS and subsequent thermical cyclization to the bromo derivatives 3 which, on catalytic dehalogenation, afforded the phthalides 4. Reaction of 11 with methanol or ethanol gave the pseudo-esters 13 and 14, resp. Short treatment of 11 with diazomethane on the other hand yielded the methyl formyl benzoates 15b to 15e. Prolonged reaction (several hours) gave the oxiranyl compounds 17; in addition, the acetonyl derivatives 18 were also found, obviously formed by a double methylene insertion into 15. All reactions proceeded with good to excellent yields.
