Selective alcoholysis of lactide catalyzed by bulky Lewis pairs of tris(pentafluorophenyl)borane and phosphines
作者:Yuushou Nakayama、Kentaro Yamaguchi、Ryo Tanaka、Takeshi Shiono
DOI:10.1016/j.mcat.2022.112121
日期:2022.2
this catalyst system, the reactions of L-LA with isopropyl alcohol or tert‑butyl alcohol were much slower than those with primary alcohols such as benzyl alcohol, 1-butanol, and ethanol. Thus, the high chemo-selectivity of the B(C6F5)3-phosphine systems should come from their steric hindrance which differentiates the reactivity to the primary hydroxy group and that to the secondary one.
本研究调查了由路易斯对 B(C 6 F 5 ) 3 -膦催化的丙交酯的选择性醇解。在本研究中检测的膦中,三环己基膦 (Cy 3 P) 在该系统中表现出高活性和高选择性。L-丙交酯( L -LA)与苯甲醇通过 B(C 6 F 5 ) 3 -Cy 3 P 体系醇解生成高转化率(~96%)和高选择性(>91%)的乳酸苄酯。饲料范围广 [L-LA] 0 :[酒精] 0在 100 °C 的甲苯中的摩尔比。在该催化剂体系中,L-LA 与异丙醇或叔丁醇的反应比与苯甲醇、1-丁醇和乙醇等伯醇的反应慢得多。因此,B(C 6 F 5 ) 3 -膦系统的高化学选择性应该来自于它们的空间位阻,它区分了对伯羟基的反应性和对仲羟基的反应性。