Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents
作者:Daisuke Hirose、Martin Gazvoda、Janez Košmrlj、Tsuyoshi Taniguchi
DOI:10.1039/c6sc00308g
日期:——
work as organocatalysts for Mitsunobu reactions because they provide ethyl 2-arylazocarboxylates through aerobic oxidation with a catalytic amount of iron phthalocyanine. First, ethyl 2-(3,4-dichlorophenyl)hydrazinecarboxylate has been identified as a potent catalyst, and the reactivity of the catalytic Mitsunobu reaction was improved through strict optimization of the reaction conditions. Investigation
2-芳基肼甲酸乙酯可用作光延反应的有机催化剂,因为它们通过有氧氧化与催化量的铁酞菁提供 2-芳基偶氮甲酸乙酯。首先,2-(3,4-二氯苯基)肼甲酸乙酯已被确定为一种强效催化剂,通过严格优化反应条件,提高了催化Mitsunobu反应的反应性。对 2-芳基肼甲酸乙酯和相应偶氮形式的催化性能的研究使我们发现了一种新的催化剂,即 2-(4-氰基苯基)肼甲酸乙酯,这扩大了底物的范围。用这些新试剂对 Mitsunobu 反应的机理研究强烈表明甜菜碱中间体的形成就像在典型的 Mitsunobu 反应中一样。从绿色化学的角度来看,与铁催化剂一起使用大气氧作为牺牲氧化剂是方便和安全的。此外,与典型的偶氮试剂如偶氮二甲酸二乙酯 (DEAD) 相比,开发的 Mitsunobu 试剂的热分析支持足够的热稳定性。该催化体系实现了Mitsunobu反应的实质性改进,将适用于实际合成。