multisubstituted 1,3‐dienes by α‐exclusive alkylidenation of crotonic derivatives has been developed. This protocol, mediated by titanium tetrachloride chelation, features excellent regio‐ and stereoselectivity, mild reaction conditions, easy operation and wide substrate scope. Conversions of the derived dienes to other useful molecules were also explored.
In the diene synthesis with nitrosobenzenes, 1-arylbutadiene-2-carboxylic acids give, regiospecifially, adducts of structure 3. Substituents in the nitrosobenzene derivative have a strong influence on the rate of the cycloaddition, substituents in the aryl group of the diene almost none.
A color photographic light-sensitive material comprises a support and thereon a hydrophilic colloidal layer comprising a nondiffusible coupler and a hydrophilic colloidal layer comprising an aromatic primary amine developing agent and/or a precursor thereof. The color photographic light-sensitive material further comprises a polymer layer at the furthest position from the support on the same side of said hydrophilic colloidal layer, which polymer layer is permeable to an alkaline processing liquid but less permeable to said aromatic primary amine developing agent and/or precursor thereof.
Thermal ring annulation of .alpha.-vinylcinnamate methyl esters. A method for the generation of 3,4-dihydro-2-naphthoate and 2-naphthoate methyl esters
作者:Joseph R. Zoeller
DOI:10.1021/jo00255a010
日期:1988.9
McIntosh, John M.; Hayes, Ivy E. E., Canadian Journal of Chemistry, 1987, vol. 65, p. 110 - 113