Stereoelectronic factors in bridgehead C–H bond insertion: studies toward the total synthesis of maoecrystal V

A strategy for the total synthesis of maoecrystal V is presented. The key interior vicinal quaternary carbon centers will be formed via sequential bridgehead C–H bond insertion and enolate functionalization. Studies herein validate the C–H bond insertion as feasible in model studies, though there are significant effects on the selectivity for the bridgehead position from neighboring groups. Both inductive electron withdrawing elements and sterics play a role in deactivating that position, with the former having a greater effect. Forming the second quaternary carbon is possible via enolate acylation and alkylation. Lastly, an approach to synthesize the cyclohexenone ring of maoecrystal V is described.

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