81423-75-8Relevant academic research and scientific papers
Reactions of Vinylphosphonates. 2. Synthesis of Functionalized Dienes, Trienes, and Their Analogues. Synthetic Aplications to Regioselectively Functionalized Benzene Derivatives
Minami, Toru,Nishimura, Katsuhide,Hirao, Ichiro,Suganuma, Hiroyuki,Agawa, Toshio
, p. 2360 - 2363 (2007/10/02)
The phosphoryl-stabilized carboanions prepared from vinylphosphonates 1a,b and various carbanions 2a-c react with aldehydes 3 to give olefins having various functional groups.The dienes 5c-g produced by the reaction using α,β-unsaturated aldehydes and a methyl (methylsulfinyl)methyl sulfide carbanion (2b) easily undergo thermolysis to afford reactive intermediate 1-methylthio 1,3,5-trienes, which are converted into the 1,4-disubstituted benzenes 7a-e in 27-56percent overall isolated yields via the electrocyclic reaction into cyclohexadienes and subsequent elimination of methanethiol.Thermolysis of the reaction product using ethyl α-(diethylphosphono)acrylate (1a), 2b, and 1,4-bis(2-formylethenyl)benzene (3g) produces 4,4''-bis(ethoxycarbonyl)-1,1':4',1''-terphenyl (7f) in 16percent yield.The reaction using an ethyl (methylthio)acetate carbanion (2c) instead of 2b gives thermally stable dienes 5i-l in 38-52percent yields.Oxidation of the dienes 5i,k,l followed by thermolysis, leads to the 1,2,4-trisubstituted (8a,b) and 1,2-disubstituted benzenes (9).Similar treatment of the product 5m derived from 1a, 2c, and 3-phenylpropargylaldehyde (3f) produces a mixture of 2,4-bis(ethoxycarbonyl)biphenyl (8a) and ethyl 4-(ethoxycarbonyl)-7-phenylhepta-2,4-dien-6-ynoate (11) in 23percent and 32percent yields.
