Synthesis of Forms of a Chiral Ruthenium Complex Containing a Ru-Colefin(sp2) Bond and Their Application to Catalytic Asymmetric Cyclopropanation Reactions

Hayato Inoue; Nga Phan Thi Thanh; Ikuhide Fujisawa; Seiji Iwasa

doi:10.1021/acs.orglett.0c00050

Synthesis of Forms of a Chiral Ruthenium Complex Containing a Ru-C_olefin(sp²) Bond and Their Application to Catalytic Asymmetric Cyclopropanation Reactions

Org Lett. 2020 Feb 21;22(4):1475-1479. doi: 10.1021/acs.orglett.0c00050. Epub 2020 Jan 28.

Authors

Hayato Inoue¹, Nga Phan Thi Thanh¹, Ikuhide Fujisawa¹, Seiji Iwasa¹

Affiliation

¹ Department of Applied Chemistry and Life Science , Toyohashi University of Technology , 1-1 Hibarigaoka , Tempaku, Toyohashi , Aichi 441-8580 , Japan.

PMID: 31990195
DOI: 10.1021/acs.orglett.0c00050

Abstract

Organometallic complexes [Ru-C_olefin(sp²)-Ru(II)-Pheox 2a-2d] containing a Ru-C_olefin(sp²) bond have been prepared from unsaturated chiral oxazoline derivatives and evaluated for asymmetric cyclopropanation reactions. The corresponding optically active cyclopropanes were obtained with high yields and high stereoselectivities (≥99/<1 trans/cis, 99% trans ee). The enantioselectivities were found to be affected by the geminal substituent on the Ru-C(sp²) bond. In particular, Ru(II)-Prox catalyst 2c, in which there was no geminal substituent on the metal, was shown to have the highest enantioselectivities.