Regiodivergent C−H and Decarboxylative C−C Alkylation by Ruthenium Catalysis:
<i>ortho</i>
versus
<i>meta</i>
Position‐Selectivity
作者:Korkit Korvorapun、Marc Moselage、Julia Struwe、Torben Rogge、Antonis M. Messinis、Lutz Ackermann
DOI:10.1002/anie.202007144
日期:2020.10.12
Ruthenium(II)biscarboxylate complexes enabled the selectivealkylation of C−H and C−C bonds at the ortho‐ or meta‐position. ortho‐C−HAlkylations were achieved with 4‐, 5‐ as well as 6‐membered halocycloalkanes. Furthermore, the judicious choice of the directing group allowed for a full control of ortho‐/meta‐selectivities. Detailed mechanistic studies by experiment and computation were performed and
Stereoisomerization of the Bornyl Radical during Aliphatic Nucleophilic Substitutions.
作者:Kim Daasbjerg、Henning Lund、Carl Erik Olsen、Kim Simonsen、György Liptay、Katrin Trautwein-Fritz、Joseph Stackhouse、Mauro I. Ciglic、Monika Haugg、Nathalie Trabesinger-Rüf、Elmar G. Weinhold
DOI:10.3891/acta.chem.scand.50-0299
日期:——
The mechanism of the reaction between the anion of 4-methoxycarbonyl-1-methyl-1,4-dihydropyridine (1(-)) and endo-2-bromo-1,7,7-trimethylbicyclo[2.2.1]heptane (bornyl bromide) and between 1(-) and exo-2-bromo-1,7,7-trimethylbicyclo[2.2.1]heptane (isobornyl bromide) has been investigated. In both cases the endo and exo substitution products were produced with a small dominance of the inversion product. While the product distribution was independent of temperature for the reaction with bornyl bromide, the yield of the endo-product increased at lower temperatures in the reaction with isobornyl bromide. Clear-cut evidence of a mechanism change in the latter case was not observable in an Arrhenius plot. Different mechanistic interpretations as regards to S(N)2 and electron transfer reactions are discussed.
Daasbjerg, Kim; Hansen, John N.; Lund, Henning, Acta Chemica Scandinavica, 1990, vol. 44, # 7, p. 711 - 714