84670 20200221144231.0 doi 10.1002/chem.201601301 sideral 98884 ART-2016-98884 eng (orcid)0000-0002-0116-9743 Méndez, Isabel Temperature Dual Enantioselective Control in a Rhodium-Catalyzed Michael-Type Friedel-Crafts Reaction: A Mechanistic Explanation 2016 Access copy available to the general public Unrestricted By changing the temperature from 283 to 233 K, the S (99% ee)orR (96 % ee)enantiomer of the Friedel–Crafts (FC) adduct of the reaction between N-methyl-2-methylindole and trans-b-nitrostyrene can be obtained by using (S Rh ,R C )-[(h 5 -C 5 Me 5 )Rh{(R)-Prophos}(H 2 O)][SbF 6 ] 2 as the catalyst precursor.This catalytic systempresents two otheruncom - mon features:1)The ee changes with reactio ntime showing trends that depend on the reactiontemperature and 2) an increase in the catalyst loading results in adecrease in the ee of the S enantiom er.Detection and characteriza tion of the intermediate metal-nitroalkene and metal–aci-nitro complexes, the free aci-nitro compound, and the FC adduct-complex, together with solution NMR measuremen ts, theo- retical calculations, and kinetic stu dies have allowed us to propose two plausible alternative catalytic cycles. On the basis of these cycles,all the above -mentioned observations can be rationalized. In particular,the reversibility of one of the cycles toget her with the kinetic resolution of the intermediate aci-nitro complexes accountfor the high ee values achieved in both antipodes.Onthe other hand, the results of kinetic measurements explain the unusual effect of the increment in catalyst loading. info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio/CSD2006-0015 info:eu-repo/grantAgreement/ES/MINECO/CTQ2012-32095 info:eu-repo/grantAgreement/ES/MINECO/CTQ2015-66079-P info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 5.317 2016 CHEMISTRY, MULTIDISCIPLINARY 29 / 166 = 0.175 2016 Q1 T1 2.351 2016 Chemistry (miscellaneous) 2016 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion (orcid)0000-0002-8845-0174 Rodríguez-Martínez, Ricardo Universidad de Zaragoza (orcid)0000-0001-5823-7965 Polo, Víctor Universidad de Zaragoza (orcid)0000-0002-1735-6439 Passarelli, Vicenzo (orcid)0000-0001-8054-2237 Lahoz, Fernando J. Universidad de Zaragoza (orcid)0000-0002-7063-1292 García-Orduña, Pilar Universidad de Zaragoza (orcid)0000-0003-4196-5856 Carmona, Daniel 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 2012 755 Universidad de Zaragoza Dpto. Química Física Área Química Física 22, 31 (2016), 11064-11083 Chemistry (Weinh.) Chemistry - A European Journal 0947-6539 1833385 http://zaguan.unizar.es/record/84670/files/texto_completo.pdf Postprint 116428 http://zaguan.unizar.es/record/84670/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:84670 articulos driver 2020-02-21-13:19:31 ARTICLE