Enantioselective Protonation of Alkenyl Trifluoroacetates Catalyzed by Chiral Tin Methoxide
作者:Akira Yanagisawa、Takuya Sugita、Kazuhiro Yoshida
DOI:10.1002/chem.201302975
日期:2013.11.25
Go catalytic! A catalytic enantioselectiveprotonation of alkenyltrifluoroacetates was achieved by using an in situ generated chiraltin bromide methoxide as the chiral catalyst in the presence of methanol (see scheme). Optically active ketones containing a tertiary stereogenic center at the α‐position were obtained with enantioselectivities of up to 94 % ee.
Synthesis and Stereochemical Aspects of Ethyl 1,1a,2,3,4,5,6,6a-Octahydro-4-octylcyclopropa[f]indene-1-carboxylate
作者:Zakir Hussain、Debasis Koley、Henning Hopf
DOI:10.1002/hlca.200590262
日期:2005.12
A novel approach for the synthesis of carbene adducts 9a/9b and 10/11 is reported. Identification of the geometric and positional isomers of carbene addition was carried out by reversed-phase HPLC, and the establishment of the structure and configuration of 9a/9b was performed by means of 2D-NMR.
A mesomorphic compound of the formula (I) according to claim 1 is suitable as a component for liquid crystal composition providing improved response characteristics.
Hexamethylenetetramine/acetic anhydride-promoted alpha-methylenation of aryl alkyl ketones followed by acid-catalyzed cyclization of the resulting acrylophenones produce 2-alkyl indanones in excellent yields.