Figure 2. Internal Alkene Substrate Scope.

^aReactions were conducted on 0.62–1.94 mmol scale, with yields of diastereomerically pure product isolated after chromatographic purification unless noted otherwise. Diastereomeric ratios (d.r. values) were determined by ¹⁹F NMR of crude reaction mixtures. ^bReactions were conducted with slow addition of substrate over 2 hours and were allowed to progress with stirring for an additional 1 hour. ^cReaction was conducted at 0 °C with slow addition of substrate over 1 hour and stirring for an additional 1 hour. ^dReactions were conducted with slow addition of substrate over 2 hours and stirring for an additional 10 hours. ^eReaction was conducted in neat pyr•9HF for 12 hours. Isolated as a mixture of diastereomers. ^fReaction was conducted in neat pyr•9HF for 36 hours with a second addition of mCPBA (0.65 equiv) after 24 hours. ^gReaction was conducted with 20 equiv of HF for 24 hours. Isolated as a mixture of a diastereomers.