Table 1.

Optimization of reaction conditions

The reaction was performed on a 0.05 mmol scale. Entries 1–7, the chemical conversion of 1a was >95% determined by crude ¹H NMR. Entry 8, the chemical conversion of 1a was 23%

^aYields were determined from the isolated compound following chromatographic purification

^bEnantiomeric excesses were determined by HPLC analysis on a chiral stationary phase