Iron-catalyzed, highly regioselective synthesis of α-aryl carboxylic acids from styrene derivatives and CO2.
The iron-catalyzed hydrocarboxylation of aryl alkenes has been developed using a highly active bench-stable iron(II) precatalyst to give α-aryl carboxylic acids in excellent yields and with near-perfect regioselectivity. Using just 1 mol % FeCl(2), bis(imino)pyridine 6 (1 mol %), CO(2) (atmospheric pressure), and a hydride source (EtMgBr, 1.2 equiv), a range of sterically and electronically differentiated aryl alkenes were transformed to the corresponding α-aryl carboxylic acids (up to 96% isolated yield). The catalyst was found to be equally active with a loading of 0.1 mol %. Preliminary mechanistic investigations show that an iron-catalyzed hydrometalation is followed by transmetalation and reaction with the electrophile (CO(2)).
School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, United Kingdom.
Mark D
MD
Greenhalgh
Stephen P
SP
Thomas
D000475:Alkenes / Q000138:chemical synthesis / Q000737:chemistry*; D002245:Carbon Dioxide / Q000138:chemical synthesis / Q000737:chemistry*; D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D006841:Hydrocarbons, Aromatic / Q000138:chemical synthesis* / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D013237:Stereoisomerism; D020058:Styrene / Q000138:chemical synthesis / Q000737:chemistry*
D000475:Alkenes; D002264:Carboxylic Acids; D006841:Hydrocarbons, Aromatic; D002245:Carbon Dioxide; D020058:Styrene; D007501:Iron