[4+2]-Cycloaddition reactions employing 2-fluoro-2-alkenal N,N-dimethylhydrazones: synthesis of 3-fluoropyridines and dihydro or tetrahydro derivatives thereof
作者:Somnath Ghosh、Manfred Schlosser
DOI:10.1016/0022-1139(93)02932-5
日期:1994.4
N,N-Dimethylhydrazones prepared from 2-fluoro-2-alkenals undergo smooth [4+2]-cycloaddition reactions with methyl acrylate, dimethyl acetylenedicarboxylates and quinones. The resulting 3-fluoropyridines, or dihydro and tetrahydro derivativesthereof, can be isolated in fair to good yield.
Swapped selectivities: The use of tailor‐made catalysts results in anomalous endo/exo selectivities and high enantioselectivities in the Diels–Alder reactions of cyclopentadiene with different acroleins (see scheme). These supramolecular catalysts are prepared in situ from chiral diols, arylboronic acid, and tris(pentafluorophenyl)borane, and can discriminate the re/si face of the dienophile as well
Synthesis of fluorinatedanalogs of some dienic insect sex pherormones through a stereocontrolled Wittig reaction of β-fluorinated aldehydes with the appropriate ω-functionalized ylides is reported. Some features of the 1H and 19F NMR spectra of these analogs are also discussed.
据报道,通过β-氟化醛与适当的ω-官能化的乙炔的立体控制的Wittig反应,合成了一些二齿昆虫性信息素的氟化类似物。还讨论了这些类似物的1 H和19 F NMR光谱的某些特征。
Pyrazole compounds and use thereof
申请人:Sumitomo Chemical Company, Limited
公开号:US04980345A1
公开(公告)日:1990-12-25
There are disclosed a pyrazole compound represented by the formula, ##STR1## wherein the substituents of R.sub.1 to R.sub.7 and the sumbol Z have the specified meanings as described in the text, an insecticidal, acaricidal and fungicidal composition containing the same, use of said composition for control of insects, acarids and fungi and a method of preparing said compound, and its intermediate.