Lactone; XIII.<sup>1</sup>Phasentransfer-Oxidation nach Grignardierung: Eine einfache Synthese γ,γ-disubstituierter γ-Butyrolactone aus γ-Butyrolacton
作者:Jochen Lehmann、Norbert Marquardt
DOI:10.1055/s-1987-28171
日期:——
Lactones; XIII. Grignard Reaction Followed by Phase-Transfer Oxidation: A Convenient Synthesis of γ,γ-Disubstituted γ-Butyrolactones from γ-Butyrolactone Grignard Reaction of γ-butyrolactones, followed by oxidation of the resulting reaction mixture produces symmetrically γ,γ-dialkylared diarylated γ-butyrolactones. Phase transfer oxidation with potassium permanganate in benzene/water proves to be the best out of twelve examined oxidation methods. The synthesis is unsuccessful with sterically hindered or oxidizable Grignard reagents.
Efficient chemoselective addition of Grignard reagents to carbonyl compounds in 2-methyltetrahydrofuran
作者:Weihui Zhong、Yaotiao Wu、Xingxian Zhang
DOI:10.3184/030823409x460939
日期:2009.6
Compared with tetrahydrofuran (THF) as a solvent for the addition reactions between Grignard reagents and carbonyl compounds 2-methyltetrahydrofuran affords the corresponding adducts in higher yields with higher chemoselectivities. Moreover, 2-methyltetrahydrofuran can be readily recycled and reused, which lowers the cost of the process and makes the reaction greener.
A device body is equipped with a heater unit (3) and a thermal evaporating agent (9) is filled in a tank (6), and a leading end of a core (8) for sucking up the thermal evaporating agent which is inserted is the tank (6) is inserted into the heater unit (3). The heater unit (3) is in an annular shape and is incorporated with a transformerless exothermic body (10). The transformerless exothermic body (10) is a positive temperature thermistor and the voltage-current characteristic thereof has a region, over the range of at least 100V to 240V of applied voltage, which satisfies the conditions ofVx + Iy = a (a is constant) in orthogonal coordinates in which a longitudinal axis is a voltage Vx and a lateral axis is a current Iy. Therefore, even though the applied voltages are 100 V and 240 V, the change of consumed current, P=VI is small and there causes no difference in their exothermic temperatures in the range of the applied voltages of 100 V to 240 V. Thus, even though the applied voltage is 100 V or 240 V, there causes no difference in consuming time of the thermal evaporating agent.