22463-33-8Relevant academic research and scientific papers
1,4-Addition of Triorganozincates and Silyldiorganozincates to α,β-Unsaturated Ketones
Tueckmantel, Werner,Oshima, Koichiro,Nozaki, Hitosi
, p. 1581 - 1593 (2007/10/02)
Lithium and magnesium triorganozincates, prepared by combination of ZnCl2(TMEDA) with 3 molar equivalents of RLi or RMgX, or from dialkylzinc and 1 molar equivalent of RLi or RMgX, react with 2-cyclohexen-1-one (1) under mild conditions to produce moderate to good yields of the 1,4-addition products 2.The approximate reactivity order obtained from the product distribution using unsymmetrical zincates is tBuCH2 tBu, Me Me2PhSi.The latter groups are transferred with good selectivity from mixed reagents derived from Me2Zn.This sequence differs strikingly from that exhibited by unsymmetrical cuprates which transfer neopentyl very easily, and also tert-butyl more easily than the corresponding zincates.The methylation with Me3ZnLi is catalyzed by cobalt complexes.Other enones (7-13) generally give poor yields, and the cobalt-catalyzed methylation of isophorone (3) is complicated by a Kharasch-type deconjugation.Mixed silyldialkylzincates, Me2PhSiZnR2Li, produce the β-silyl ketones from a variety of unhindered or moderately hindered enones in practically useful yields; one example of an α,β-unsaturated ester (12) is also included.
CYCLOADDITION OF DICLOROKETENE WITH FUNCTIONALIZED CYCLOALKENES. SYNTHESIS OF BICYCLOOCTANONE-3-YL DERIVATIVES AND OF 3,4-DICARBOXYMETHOXY-1-METHYLBICYCLOOCTAN-7-ONE
Rosini, Goffredo,Ballini, Roberto,Zanotti, Valerio
, p. 1085 - 1090 (2007/10/02)
Dichloroketene reacts with some cycloalkenes in wich an ester function is in homoallylic or in an even more remote position with respect to sp2 carbon atoms.In fact acetate and benzoate of 3,5,5-trimethylcyclohex-3-en-1-ol and 1,2-dicarbomethoxy-4-methyl-cyclohex-4-ene undergo 2+2 cycloaddition of dichloroketene to produce the corresponding bicyclooctanone derivatives in 60-65percent yield.In the latter case the process occurs regiospecifically to give 3,4-dicarboxymethoxy-1-methylbicyclooctan-7-one as product after dechlorination.The Hassner zinc dehalogenation method of generating dichloroketene is the best procedure.
STEREOCHIMIE-LII. CONTROLE ORBITALAIRE DE LA STEREOCHIMIE DES REACTIONS-III EFFETS DES GROUPES β-FLUORO ET β-CYANO SUR LA STEREOCHIMIE ET LA CINETIQUE DE LA REDUCTION DE CYCLOHEXANONES PAR LE TRITERTIOBUTOXYALUMINOHYDRURE DE LITHIUM
Agami, C.,Kazakos, A.,Levisalles, J.,Sevin, A.
, p. 2977 - 2981 (2007/10/02)
The respective influences of β-fluoro and β-cyano groups on the reduction of ketones by Li(t-BuO)3AlH on the stereoselectivities of the reduction with and without added cryptands, and with and without added alkyl fluoride and nitrile, were compared with ab initio calculations using the frontier orbitals of analogous carbonyl compounds to give energy values
