RESUMO
Herein, we report the asymmetric Ru/cinchonine dual catalysis that provides straightforward access to enantioselective synthesis of C-3 substituted phthalides via tandem C-H activation/Michael addition cascade. The use of readily accessible and less expensive [RuCl2(p-cym)]2 and cinchonine catalyst for the one-pot assembly of chiral phthalides greatly overcomes the present trend of using highly sophisticated catalysts. The developed method provides access to both enantiomers of a product using pseudoenantiomeric cinchona alkaloids as catalysts streamlining the synthesis of phthalide in both the optically active forms.
Assuntos
Acrilatos , Alcaloides de Cinchona , Benzoatos , Benzofuranos , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
Enantioselective total synthesis of (+)-sapinsigin H, (+)-agallochaol C, and (+)-16α, 17-dihydroxy-atisan-3-one has been accomplished starting from enantiopure Wieland-Miescher ketone. Key features of the syntheses include a benzannulation step to construct the tricyclic core, an oxidative dearomatization step to generate the diene, and a Diels-Alder reaction with ethylene gas to establish the bicyclo[2.2.2]octane framework. Efficient late-stage functionalisation of the A-ring by aerobic oxidation and Baeyer-Villiger oxidation completed the atisane target molecules.
RESUMO
Translevator perineal hernias are rare pelvic floor defects that can be classified based on their anatomical location as either anterior or posterior relative to the transverse perineal muscle. This report describes an unusual clinical and radiological presentation of a posterior perineal hernia in an elderly lady. The case highlights the limitations of CT when findings are not definitive and the role of MRI as a superior problem-solving tool to better delineate the pelvic anatomy, exclude sinister pathology and confirm the diagnosis.