Table 2.

Evaluation of Ketone Scope.

^aYields indicate isolated yield of product as a mixture of two diastereomers on a 0.5 mmol scale. 1.2 equiv of allene was used, see Supporting Information for further details. Diastereomeric ratios were determined by ¹H NMR spectroscopy for both the crude and purified products using 1,1,2,2-tetrachloroethane as internal standard;. Enantiomeric excesses determined by HPLC or SFC analysis on commercial chiral columns; enantiomeric ratios of minor diastereomers indicated in parentheses. Yields, diastereomeric ratios, and enantiomeric excesses are the averages for two identical runs.

^bThe reaction was conducted without tert-butanol;

^cThe diastereomeric ratio was determined using both GC and chiral SFC analysis.