In the context of synthetic efforts targeting the alkaloid lyconadin A, scalemic epoxide 25 was prepared by a highly stereoselective sequence involving a Myers alkylation and a Shi epoxidation. Ring-opening of this epoxide with a vinylcopper complex afforded alcohol 26 instead of the expected product 27. An unusual Lewis acid promoted Payne rearrangement of an α-trityloxy epoxide is proposed to account for this outcome.
在针对生物碱lyconadin A的合成努力的背景下,通过涉及Myers烷基化和Shi环氧化的高立体选择性序列制备了规模化环氧化物25。使用乙烯铜络合物开环这种环氧化物,得到了醇26,而不是预期的产物27。提出了一种不寻常的Lewis酸促进的Payne重排反应,用来解释这一结果。