MICHAEL ADDITION-PETERSON OLEFINATION SEQUENCE OF METHYL 2-(TRIMETHYLSILYL)ACRYLATE AS A CONVENIENT METHOD FOR CONSECUTIVE FORMATION OF CARBON-CARBON SINGLE AND DOUBLE BONDS
作者:Otohiko Tsuge、Shuji Kanemasa、Yusuke Ninomiya
DOI:10.1246/cl.1984.1993
日期:1984.11.5
A convenient method for the consecutive formation of carbon–carbon single and double bonds is presented with the example of the Peterson olefination of the carbanions resulted from the Michaeladdition of organometallics to methyl 2-(trimethylsilyl)acrylate.
The Diels–Aldercycloaddition of 4-methylene-1,5-hexadien-3-ols with olefinic dienophiles such as dimethyl maleate, fumarate, and N-methylmaleimide produces 1-(1-cyclohexenyl)-2-propen-1-ols. These diene alcohols are oxidized with activated manganese(IV) oxide to give dienones, which are then treated with acid catalysts to undergo ready electrocyclization leading to hexahydroindenones with functional
depending upon the reaction conditions and the reactivity of donor molecules. The adduct anions, both 1:1 and 1:2 types, are quenched with alkyl halides or water in a highly stereoselective manner to produce α-silylated esters. A rigid intramolecular chelation working in the adduct anions is partly responsible for the high selectivity.
Michael Addition of Methyl 2-(Trimethylsilyl)propenoate with Organomagnesiums or Organolithiums Leading to 1:1 and/or 2:1 Adducts and Subsequent Peterson Olefination by Condensation with Carbonyl Compounds
Michael addition of methyl 2-(trimethylsilyl)propenoate with organomagnesiums or organolithiums leads to 1:1 and/or 1:2 adduct anions which can be utilized in the subsequent step of Peterson olefination with carbonyl compounds. The 1:1/1:2 ratio depends upon the nature of donor molecules, the reaction conditions such as reaction temperature, polarity of solvent, and rate of addition of the acceptor
Construction of [4.3.1]Propellanes via Molybdenum Fischer Carbene Complexes
作者:Thomas M. Bertolini、Que Huong Nguyen、Daniel F. Harvey
DOI:10.1021/jo020378a
日期:2002.11.1
molybdenum Fischer carbene complexes with 6-methylene-7-octen-1-yne derivatives at 40 degrees C generates substituted tricyclo[4.3.1.0(1,6)]deca-2,4-dienes in good yield. Pentacarbonyl(butylmethoxycarbene)molybdenum(0) afforded the highest cyclization yields (54%), while the analogous chromium carbene complex gave no reaction. The range of dienyne substrates that participate in this reaction is explored