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Communication | Regular issue | Vol 85, No. 12, 2012, pp.2927-2932
Published online, 25th October, 2012
DOI: 10.3987/COM-12-12599
Synthesis of (±)-Esermethole via an Intramolecular Carbamoylketene-Alkene [2+2] Cycloaddition

Tsukasa Ozawa, Makoto Kanematsu, Hiromasa Yokoe, Masahiro Yoshida, and Kozo Shishido*

*Graduate School of Pharmaceutical Sciences, University of Tokushima, 1-78-1 Sho-machi, Tokushima 770-8505, Japan


A synthesis of (±)-esermethole (2), a synthetic precursor of physostigmine (1), has been accomplished by using an intramolecular carbamoylketene-alkene [2+2] cycloaddition followed by nitrone-mediated regioselective ring expansion for the construction of the basic carbon framework of 2 as the key steps.