1,5-Benzothiazepine frameworks are highly relevant in medicinal chemistry. Reported catalytic asymmetric approaches to these scaffolds have targeted 2,3-dihydro-1,5-benzothiazepin-4-ones, leaving the corresponding amines (2,3,4,5-tetrahydro-1,5-benzo-thiazepines) out of reach. Herein, we present the… Click to show full abstract
1,5-Benzothiazepine frameworks are highly relevant in medicinal chemistry. Reported catalytic asymmetric approaches to these scaffolds have targeted 2,3-dihydro-1,5-benzothiazepin-4-ones, leaving the corresponding amines (2,3,4,5-tetrahydro-1,5-benzo-thiazepines) out of reach. Herein, we present the first entry to these important compounds in enantioenriched form. Our approach is based on the catalytic asymmetric sulfa-Michael addition of 2-aminothiophenols to trans-chalcones, followed by intramolecular reductive amination. Both reactions have required a careful study to solve several challenging issues. The resulting optimized two-step protocol afforded a range of 2,3,4,5-tetrahydro-1,5-benzothiazepines as single trans-diastereoisomers in moderate to good yields and enantioselectivities.
               
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