The Important Role of the Byproduct Triphenylphosphine Oxide in the Magnesium(II)-Catalyzed Enantioselective Reaction of Hemiacetals and Phosphorus Ylides

Linqing Wang; Dongxu Yang; Dan Li; Xihong Liu; Pengxin Wang; Kezhou Wang; Haiyong Zhu; Lutao Bai; Rui Wang

doi:10.1002/anie.201804177

The Important Role of the Byproduct Triphenylphosphine Oxide in the Magnesium(II)-Catalyzed Enantioselective Reaction of Hemiacetals and Phosphorus Ylides

Angew Chem Int Ed Engl. 2018 Jul 16;57(29):9088-9092. doi: 10.1002/anie.201804177. Epub 2018 Jun 12.

Authors

Linqing Wang¹, Dongxu Yang¹, Dan Li¹, Xihong Liu¹, Pengxin Wang¹, Kezhou Wang¹, Haiyong Zhu¹, Lutao Bai¹, Rui Wang¹

Affiliation

¹ Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, P. R. China.

PMID: 29766625
DOI: 10.1002/anie.201804177

Abstract

By employing a simple in situ generated magnesium catalyst, a direct asymmetric reaction between hemiacetals and phosphorus ylides was achieved through a tandem Wittig-oxa-Michael reaction sequence. Enantioenriched chromans, isochromans, and tetrahydropyrans were obtained in good chemical yields, and (-)-erythrococcamide B was synthesized in enantioenriched form. The byproduct triphenylphosphine oxide was identified as a necessary additive for this process.

Keywords: asymmetric synthesis; chiral ethers; hemiacetals; magnesium; phosphorus ylides.