M.C. White/Q Chen, Chem 153 Q&A-343 Week of december 2. 2002 Murai has described the synthesis of butanolides from a three component coupling shown below Propose a mechanism for this process Ru3 CO12(2.5 mol%) RuCO3 cO reductive elimination The authors propose that the o, -chelate ruthenium complex reacts with ethylene to form a metallacycle in which the Ru-s bond remains intact Murai,S.JACS1999,7160-7161M.C. White/Q. Chen, Chem 153 Q&A -343- Week of December 2, 2002 N S O Me N S O Me N S Me OCRu O OC CO N S O O Me N S O O Me CO Murai has described the synthesis of butanolides from a three component coupling shown below. Propose a mechanism for this process. Ru3CO12 (2.5 mol%) tol., 140 °C, 20h "RuCO3" Murai, S. JACS 1999, 7160-7161. ethylene (3 atm) CO (5 atm) S O N Me Ru "σ,σ-chelate ruthenium complex" The authors propose that the σ,σ-chelate ruthenium complex reacts with ethylene to form a metallacycle (CO)3 in which the Ru-S bond remains intact. S O N Me Ru (CO)3 S N Me Ru (CO)2 O O reductive elimination CO insertion O M M O