Interestingly, the yields obtained are considerably lower than the almost quantitative yields obtained for simple aliphatic substrates (see Scheme 2 above). However, remaining starting material is still present in all cases. The overall mass balances that are consistently >90% reflect very little side reactivity and clean reaction profiles. This suggests that either longer reaction times or faster turnover may improve the yields obtained under standard conditions. Indeed, when extending the reaction time from 48 h to 72 h with substrate 16, an increase of 11% was observed (63% vs. 52% assay yield). An increase in oxidant loading (from 2 to 3 eq. PhCO 3 t Bu) had a similar beneficial effect (60% vs. 52% assay yield 16a) after 48 h. Overall, these data imply that higher yields are achievable with lower yielding substrates with relatively straightforward optimizations.