DOI: 10.1021/acs.joc.6c01394 ISSN: 0022-3263
Organocatalyzed Asymmetric Formal [3+2] Cycloaddition between Cyclic Nitrones and Meldrum’s Acid for the Formal Total Synthesis of (−)-Crispine A
Yasunori Toda, Saho Mizuki, Kenshiro Abe, Koshi Yamana, Shunsuke Naito, Fumiya Iwakuma, Hiroyuki SugaAbstract
We report herein the formal total synthesis of crispine A. The key feature of our synthetic route is an asymmetric formal [3+2] cycloaddition between cyclic nitrones and Meldrum’s acid using a quinine-derived chiral amine-urea. The cycloaddition provided an optically active isoxazolidinone, which was successfully converted to a common precursor of crispine A.