title: Regioselective chromatic orthogonality with light-activated metathesis catalysts.
abstract: The ability to selectively guide consecutive chemical processes towards a preferred pathway by using light of different frequencies is an appealing concept. Herein we describe the coupling of two photochemical reactions, one the photoisomerization and consequent activation of a sulfur-chelated latent olefin-metathesis catalyst at 350 nm, and the other the photocleavage of a silyl protecting group at 254 nm. Depending on the steric stress exerted by a photoremovable neighboring chemical substituent, we demonstrate the selective formation of either five- or six-membered-ring frameworks by light-triggered ring-closing metathesis. The orthogonality of these light-induced reactions allows the initiation of these processes independently and in interchangeable order, according to the wavelength of light used to promote them.
authors.affiliation: Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel).
authors.forename: Efrat
authors.initials: E
authors.lastname: Levin
authors.affiliation: Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel).
authors.forename: Sudheendran
authors.initials: S
authors.lastname: Mavila
authors.affiliation: Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel).
authors.forename: Or
authors.initials: O
authors.lastname: Eivgi
authors.affiliation: Department of Chemical Engineering, Shamoon College of Engineering, Ashdod 77245 (Israel).
authors.forename: Eyal
authors.initials: E
authors.lastname: Tzur
authors.affiliation: Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel). lemcoff@bgu.ac.il.
authors.forename: N Gabriel
authors.initials: NG
authors.lastname: Lemcoff
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D003516:Cycloparaffins / Q000138:chemical synthesis* / Q000737:chemistry; D008027:Light; D015394:Molecular Structure; D055668:Photochemical Processes; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D003516:Cycloparaffins
keywords: chromatic orthogonality; cyclization; heterocycles; olefin metathesis; photochemistry