3183-57-1Relevant academic research and scientific papers
Enantioselective borohydride reduction of aliphatic ketones catalyzed by ketoiminatocobalt(iii) complex with 1-chlorovinyl axial ligand
Tsubo, Tatsuyuki,Chen, Hsiu-Hui,Yokomori, Minako,Fukui, Kosuke,Kikuchi, Satoshi,Yamada, Tohru
supporting information; experimental part, p. 780 - 782 (2012/09/22)
For the enantioselective borohydride reduction of aliphatic ketones, the optically active ketoiminatocobalt(II) catalysts was successfully designed based on their axial ligand. Instead of chloroform for the aryl ketone reduction, various axial ligand precursors were examined for the aliphatic ketone. Consequently, 1, 1, 1-trichloroethane was found to be the most effective activator of the cobalt(II) complexes to generate the corresponding 1-chlorovinyl cobalt(III) derivatives as the reactive intermediate. Several aliphatic ketones were successfully reduced to afford the corresponding secondary alcohols with high enantioselectivities.
Reductive opening of 2-phenyl-1,3-dioxolanes by a naphthalene-catalysed lithiation: Synthetic applications
Gil, Juan F.,Ramon, Diego J.,Yus, Miguel
, p. 9535 - 9546 (2007/10/02)
The reaction of 2-phenyl-1,3-dioxolanes 1a,b with an excess of lithium powder in the presence of a catalytic amount of naphthalene (4 mol %) in tetrahydrofuran at -40°C followed by successive reaction with an electrophile and final hydrolysis with water at the same temperature yields the corresponding monoprotected 1,2-diols 2aa-2bf. The same process but allowing to rise the temperature to 20°C before the hydrolysis affords alcohols 3aa-3bd. The use of 2,2-diphenyl-1,3-dioxolane 1d, under similar reaction conditions as for compounds 2, permits the isolation of 2,2-diphenylalcohols 11da-11dc, resulting from the reaction with two different electrophiles. A mechanistic rationalization for all processes is given.
Wanderungstendenzen cyclischer, polycyclischer und methylverzweigter Alkylreste bei der Beckmann-Umlagerung
Langhals, Heinz,Ruechardt, Christoph
, p. 3831 - 3854 (2007/10/02)
The migration aptitudes of polycyclic bridgehead groups, cycloalkyl groups as well as of β-, γ- and δ-branched alkyl groups in the Chapman variant of the Beckmann rearrangement were determined.From these data it is concluded that at transition state 2 the migrating group is not resembling a planarised carbenium ion R+, but rather a pentacoordinated carbonium ion structure.Because only small geometrical changes occur in the migrating group vertical stabilisation of charge at transition state is believed to have significant influence on the migration aptitudes.
