Isothiourea-catalyzed asymmetric synthesis of β-lactams and β-amino esters from arylacetic acid derivatives and N-sulfonylaldimines.
نویسندگان
چکیده
The isothiourea HBTM-2.1 (5 mol %) catalyzes the asymmetric formal [2 + 2] cycloaddition of both arylacetic acids (following activation with tosyl chloride) and preformed 2-arylacetic anhydrides with N-sulfonylaldimines, generating stereodefined 2,3-diaryl-β-amino esters (after ring-opening) and 3,4-diaryl-anti-β-lactams, respectively, with high diastereocontrol (up to >95:5 dr) and good to excellent enantiocontrol. Deprotection of the N-tosyl substituent within the β-lactam framework was possible without racemization by treatment with SmI2.
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ورودعنوان ژورنال:
- The Journal of organic chemistry
دوره 79 4 شماره
صفحات -
تاریخ انتشار 2014