title: Stereodivergent Carbamate Synthesis by Selective in Situ Trapping of Organic Carbonate Intermediates.
abstract: Trans carbamates have been prepared in a diastereoselective approach by a judicious one-pot combination of organic carbonates, prepared in situ, and suitable amine reagents under appropriate reaction conditions. This unprecedented approach allows for stereodivergence from a single oxirane substrate with easy access to both cis and trans carbamate isomers with high stereoselectivity (>19:1 d.r.). Key to the control of the diastereoselective nature of the conversions that lead to the trans carbamates is the in situ formation of trans-configured oligo/polycarbonates through Al catalysis, which provides the targeted products after aminolysis. The present results demonstrate the valorization of a renewable carbon-based reagent (CO2) into new valuable scaffolds and an unusual stereocontrol exerted through carbonate intermediates. A series of control experiments support the proposed mechanistic rationale towards the trans carbamate products, which is based on the trapping of an in situ formed trans-configured oligo/polycarbonate.
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Wusheng
authors.initials: W
authors.lastname: Guo
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Laserna
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Eddy
authors.initials: E
authors.lastname: Martin
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain.
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Escudero-Adán
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain. akleij@iciq.es.|Catalan Institute of Research and Advanced Studies (ICREA), Pg. Lluís Companys 23, 08010, Barcelona, Spain. akleij@iciq.es.
authors.forename: Arjan W
authors.initials: AW
authors.lastname: Kleij
keywords: aluminium; carbamates; carbon dioxide; diastereoselectivity; organic carbonates