414869-17-3Relevant articles and documents
Enantioselective, Noncovalent, Substrate-Directable Heck–Matsuda and Oxidative Heck Arylations of Unactivated Five-Membered Carbocyclic Olefins
de Oliveira, Juliana Manso,Angnes, Ricardo Almir,Khan, Ismat Ullah,Polo, Ellen Christine,Heerdt, Gabriel,Servilha, Bruno M.,Menezes da Silva, Vitor H.,Braga, Ataualpa A. C.,Correia, Carlos Roque Duarte
, p. 11738 - 11747 (2018)
Highly diastereo- and enantioselective, noncovalent, substrate-directable Heck desymmetrizations of cyclopentenyl olefins containing hydroxymethyl and carboxylate functional groups are presented. These conformationally unbiased cyclic olefins underwent effective arylations in yields of up to 97 %, diastereoselectivity up to >20:1, and enantiomeric excesses of up to 99 %. Noncovalent directing effects were shown to be prevalent in both Heck–Matsuda and oxidative Heck reactions, allowing the preferential formation of cis-substituted aryl cyclopentenes containing two stereocenters, including quaternary stereocenters. These results further validate the internal out-of-coordination-sphere ion–dipole interaction concept directing the reaction diastereoselectivity to the cis-Heck product. This approach is complementary to existing methods using bis-phosphine monoxide ligands to give the opposite trans-diastereoisomer. The applicability of the method is showcased by the straightforward synthesis of a potent phosphodiesterase 4 inhibitor in a diastereo- and enantioselective manner. The reaction is operationally simple and has broad scope with regard to the nature of the arenediazonium salt and boronic acid employed. The mechanism and origin of stereoselectivity were investigated with control experiments and DFT calculations that fully supported the stabilizing internal out-of-coordination-sphere ion–dipole interaction between the resident functional group and cationic palladium.
Alkylation of 4-substituted 1-acetoxy-2-cyclopentenes by using copper reagents derived from alkylmagnesium halides and copper(I) cyanide
Kobayashi, Yuichi,Ito, Michiko,Igarashi, Junji
, p. 4829 - 4832 (2002)
Alkylation of the acetates derived from 4-phenyl- and 4-butyl-2-cyclopenten-1-ols 2 was investigated with copper reagents derived from n-BuMgX (X=Cl, Br) and CuCN in 2:1 and 1:1 ratios in THF and in Et2O. cis 1,4-Isomers 4a,b (R=Ph, n-Bu) were produced regioselectively from the corresponding trans acetates 3a,b with the reagent in a 2:1 ratio of BuMgCl and CuCN in THF, while the BuMgBr-based reagents of 2:1 and 1:1 ratios in Et2O furnished cis 3,4-isomers 5a,b. A similar tendency was obtained with cis acetates 6a,b (R=Ph, n-Bu).
Stereoselective Synthesis of Aryl Cyclopentene Scaffolds by Heck-Matsuda Desymmetrization of 3-Cyclopentenol
Angnes, Ricardo A.,Oliveira, Juliana M.,Oliveira, Caio C.,Martins, Nelson C.,Correia, Carlos Roque D.
supporting information, p. 13117 - 13121 (2015/10/20)
A new enantioselective Heck-Matsuda desymmetrization reaction was accomplished by using 3-cyclopentenol to produce chiral five-membered 4-aryl cyclopentenol scaffolds in good yields and high ee's, together with some 3-aryl-cyclopentanones as minor products. Mechanistically, the hydroxyl group of 3-cyclopentenol acts as a directing group and is responsible for the cisarrangement in the formation of the 4-aryl-cyclopentenols.
