Chiral Lewis acid catalyzed asymmetric cycloadditions of carbonyl ylides generated from diazoimide derivatives and their synthetic applications to indolizidine alkaloids

Hiroyuki Suga; Yuta Hashimoto; Shingo Yasumura; Ryota Takezawa; Kennosuke Itoh; Akikazu Kakehi

doi:10.1021/jo401837d

Chiral Lewis acid catalyzed asymmetric cycloadditions of carbonyl ylides generated from diazoimide derivatives and their synthetic applications to indolizidine alkaloids

J Org Chem. 2013 Nov 1;78(21):10840-52. doi: 10.1021/jo401837d. Epub 2013 Oct 7.

Authors

Hiroyuki Suga¹, Yuta Hashimoto, Shingo Yasumura, Ryota Takezawa, Kennosuke Itoh, Akikazu Kakehi

Affiliation

¹ Department of Chemistry and Material Engineering, Faculty of Engineering, Shinshu University , Wakasato, Nagano, Nagano Prefecture 380-8553, Japan.

PMID: 24099422
DOI: 10.1021/jo401837d

Abstract

Highly enantioselective 1,3-dipolar cycloaddition reactions, catalyzed by chiral Lewis acids, between several 3-(2-alkenoyl)-2-oxazolidinones and carbonyl ylides that were generated from N-diazoacetyl lactams are described. Reactions of N-diazoacetyl lactams that possess 5-, 6-, and 7-membered rings were transformed to the corresponding epoxy-bridged indolizidines, quinolizidines, and 1-azabicyclo[5.4.0]undecanes with good to high enantioselectivities. Regio- and stereoselective ring-opening of the epoxy-bridged indolizidine cycloadduct gave the corresponding alcohol as a single diastereomer. The sequence of asymmetric cycloaddition followed by ring-opening was applied to the syntheses of several chiral indolizidine derivatives, including (+)-tashiromine.