Next, variation in the oxetane acids was investigated (5-12). A benzyl protecting group, which can be labile to photoredox conditions, was well tolerated (5q; 62%). An electron-withdrawing triflate group could also be incorporated in low yields (6q; see the Supporting Information page S36 for further discussion). TIPS-protected phenol was deprotected under the reaction conditions to give free phenol 7a. Importantly, and in contrast to our previous strategies generating oxetane carbocations, 19 electron-neutral phenyl oxetane acid was a successful substrate and provided 3,3-disubstituted oxetane 8a in 49% yield. A comparison of the reaction profiles for the formation of 2a and 8a indicated the rate of reaction was faster to form 2a, which could be correlated with the lower oxidation potential of the carboxylate from 1 (see Supporting Tables S14-S15 and Figure ). Electron-neutral oxetane analogs of ibuprofen and flurbiprofen gave oxetanes 9a and 10a, and unsubstituted biphenyl oxetane acid gave an oxetane-containing ester analog of fenbufen (11b).