Stereodivergent Carbamate Synthesis by Selective in Situ Trapping of Organic Carbonate Intermediates |
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Authors: | Dr Eddy Martin Eduardo C Escudero‐Adán Prof?Dr Arjan W Kleij |
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Institution: | 1. Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Tarragona, Spain;2. Catalan Institute of Research and Advanced Studies (ICREA), Pg. Lluís Companys 23, Barcelona, Spain |
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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. |
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Keywords: | aluminium carbamates carbon dioxide diastereoselectivity organic carbonates |
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