Fig. 8: Study toward the synthesis of (±)-esermethole and (±)-physostigmine.

A preparation of compound 30 was realized by employing domino aryne nucleophilic-ene reaction between aryne precursor 1cc-FPs and compound 26 as the key step. After obtaining compound 27, subsequent deprotection, oxidation, N-methylation, and conversion of the enol methyl ether to aldehyde gave rise to the desired compound 30. Isolated yields are given.