Synthesis of Forms of a Chiral Ruthenium Complex Containing a Ru–C<sub>olefin</sub>(sp<sup>2</sup>) Bond and Their Application to Catalytic Asymmetric Cyclopropanation Reactions
Hayato Inoue, Nga Phan Thi Thanh, Ikuhide Fujisawa, Seiji Iwasa
Abstract
Organometallic complexes [Ru–Colefin(sp2)–Ru(II)–Pheox 2a–2d] containing a Ru–Colefin(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.
Topics & Concepts
CyclopropanationGeminalChemistryRutheniumSubstituentOxazolineCatalysisMedicinal chemistryOlefin fiberDouble bondStereochemistryOrganic chemistryCyclopropane Reaction MechanismsCatalytic Alkyne ReactionsSynthetic Organic Chemistry Methods