Christov Valerij Ch, Ismailov Ismail E, Ivanov Ivaylo K
Department of Organic Chemistry & Technology, Faculty of Natural Sciences, Konstantin Preslavsky University of Shumen, 115, Universitetska str., BG-9712 Shumen, Bulgaria.
Molecules. 2015 Apr 21;20(4):7263-75. doi: 10.3390/molecules20047263.
Phosphorylated α-hydroxyallenes 1 and 2 were smoothly converted into the corresponding 2,5-dihydrofurans 3 and 4 in an 5-endo-trig cycloisomerization reaction by using 5 mol % of coinage metal salts as catalyst. Experimental conditions such as the type of the solvent, the reaction temperature, the mol % and the type of the catalyst were optimized. This mild and efficient cyclization method can be applied to dimethyl 1-hydroxyalkyl-alka-1,2-dienephosphonates 1 and 2-diphenylphosphinoyl-2,3-dien-1-ols 2a-c and 3-diphenylphosphinoyl-3,4-dien-2-ols 2d,e, furnishing 3-phosphorylated 2,5-dihydrofurans 3 and 4 in very good yields.
在5-内型-三氟环异构化反应中，以5 mol%的钱币金属盐为催化剂，磷酸化的α-羟基丙二烯1和2可顺利转化为相应的2,5-二氢呋喃3和4。对溶剂类型、反应温度、催化剂的摩尔百分比和类型等实验条件进行了优化。这种温和且高效的环化方法可应用于1-羟基烷基-链烷-1,2-二烯膦酸二甲酯1和2-二苯基膦酰基-2,3-二烯-1-醇2a - c以及3-二苯基膦酰基-3,4-二烯-2-醇2d,e，以非常高的产率得到3-磷酸化的2,5-二氢呋喃3和4。
