Stereospecific synthesis of 2‐phthalimido‐2a,3,4,5‐tetrahydro‐1H‐azeto[2,1‐d][1,5]benzothiazepin‐1‐ones

2a,4‐Disubstituted 2‐phthalimido‐2a,3,4,5‐tetrahydro‐1H‐azeto2,1‐d]1,5]benzothiazepin‐1‐ones were synthesized by cycloaddition reactions of 2,4‐disubstituted 2,3‐dihydro‐1,5‐benzothiazepines and phthalimidoketene, generated from phthalimidoacetyl chloride, in the presence of triethylamine in anhydrous benzene. The stereochemistry was discussed for the cycloaddition reaction. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:276–279, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10029