Chiral linear polymers bonded alternatively with salen and 1,4-dialkoxybenzene: synthesis and application for Ti-catalyzed asymmetric TMSCN addition to aldehydes
作者:Sekarpandi Sakthivel、Tharmalingam Punniyamurthy
DOI:10.1016/j.tetasy.2010.11.020
日期:2010.12
the asymmetric addition of TMSCN to aldehydes while the selectivity of the polymer catalyst is identical to that of the monomer. The reactions are efficient affording the cyanohydrins with up to 88% ee. The selectivity of the polymer based catalyst 9a is found to be the same to that of the monomer 10a. The reaction provides the advantages of simplified product isolation and easy recovery and recyclability
已经完成了以salen和1,4-二辛氧基苯为交替链段的手性线性聚合物1a – b的合成。GPC分析显示出对应于约3的分子量。15个(M w = 10,999,M n = 9165和PDI = 1.20)1a和ca的重复单元。 对于1b重复8(M w = 8547,M n = 7883和PDI = 1.08)重复单元。用Ti(O i Pr)4研究了聚合物1a – b作为可再循环的催化剂,用于将TMSCN不对称加成到醛中,而聚合物催化剂的选择性与单体的选择性相同。该反应有效地提供了高达88%ee的氰醇。发现基于聚合物的催化剂9a的选择性与单体10a的选择性相同。该反应的优点是简化了产物分离,并且聚合物催化剂9a易于回收和再循环,而没有任何活性或选择性的损失。