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以L-薄荷醇、4-甲基-5-羟乙基噻唑、多聚甲醛、环氧乙烷等为原料,设计合成出一类新型的噻唑基温控手性离子液体催化剂,并将其用于催化反式肉桂醛和对甲酰基苯甲酸甲酯的反应,立体选择性地合成了含有两个手性中心的取代γ-丁内酯.利用催化剂的温控性能,使反应在温控溶剂中进行,可以达到温控相分离催化的效果,实现催化剂的循环使用.选择出最佳温控溶剂为THF/正己烷(体积比为2.5∶2).以1,8-二氮杂双环[5,4,0]十一碳-7-烯(DBU)为碱试剂,在催化剂用量为反应原料的10 mol%,反应温度为35℃,反应时间为16 h的条件下,反式肉桂醛的转化率为95.4%,γ-丁内酯的选择性为80.4%,产物顺反比为3.3∶1,其ee值分别为21.3%和16.1%.考察了催化剂的循环使用性能,结果表明催化剂可循环使用4次,其催化活性基本保持不变.
A series of novel thiazolyl temperature-controlled chiral ionic liquid catalysts were designed and synthesized using L-menthol, 4-methyl-5-hydroxyethylthiazole, paraformaldehyde and ethylene oxide as raw materials, It was used to catalyze the reaction of trans-cinnamaldehyde and methyl p-formylbenzoate to synthesize the substituted γ-butyrolactone containing two chiral centers stereoselectively.Using the temperature-control property of the catalyst, Solvent to achieve the effect of temperature-controlled phase separation catalysis and realize the recycling of the catalyst.The optimum temperature control solvent is selected as THF / n-hexane (volume ratio is 2.5: 2), and 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU) is an alkaline reagent. Under the condition of 10 mol% of catalyst, reaction temperature 35 ℃ and reaction time 16 h, The conversion of aldehyde was 95.4%, the selectivity of γ-butyrolactone was 80.4%, the product was inverse ratio of 3.3:1, and the ee values were 21.3% and 16.1% respectively.The cyclic performance of the catalyst was investigated.The results showed that the catalyst Recyclable 4 times, its catalytic activity remained unchanged.