过渡金属催化的对映选择性氮宾转移到硫化物已成为快速构建对映体富集的硫酰亚胺的最有力的策略之一。然而,与贵金属相比,实现对地球丰富的高活性过渡金属氮烯中间体的立体控制仍然是一个艰巨的挑战。在此,我们公开了使用亚氨基碘烷作为氮宾前体的手性铁(II)/ N , N'-二氧化物催化的二烷基硫醚和烷基芳基硫醚的对映选择性酰亚胺化。以中等至良好的收率和高对映选择性获得了一系列手性磺酰亚胺(56 个实例,收率高达 99%,98:2 er)。通过复杂分子的后期修饰以及手性杀虫剂氟啶虫胺和相关生物活性化合物中间体的合成,证明了该方法的实用性。基于实验研究和理论计算,水键合的高自旋铁氮化物被确定为关键中间体。观察到的立体选择性源于手性洞穴中配体的酰胺单元与硫化物的大取代基之间的空间排斥。此外,二恶唑酮被证明是在铁(III)/ N , N'-二氧化物络合物存在下合适的酰基氮烯前体,导致形成对映选择性反转的硫酰亚
Enantioselective Nitrene Transfer to Sulfides Catalyzed by a Chiral Iron Complex
作者:Jun Wang、Marcus Frings、Carsten Bolm
DOI:10.1002/anie.201304451
日期:2013.8.12
Iron works: Enantioselectivenitrenetransfer to sulfide was accomplished by a chiraliron(III)/PyBOX catalyst (see scheme). Various sulfimides were thus obtained in high enantioselectivities and yields. Applications of this protocol to the syntheses of enantioenriched sulfoximines and an epoxide were also demonstrated.
Electronic effect, steric hindrance, and anchimeric assistance in oxidation of sulphides. Neighbouring-group participation through sulphur–oxygen non-bonded interaction
作者:Ferenc Ruff、Árpád Kucsman
DOI:10.1039/p29880001123
日期:——
set of sulphides o- and p-XC6H4SMe, the electroniceffect, sterichindrance, and anchimericassistance for electrophilic Cl+ addition by TsNHCl and O-transfer by NalO4 were investigated by a kinetic method. The stericeffect and anchimericassistance of the ortho-substituents were evaluated by comparing the reactivity of ortho- and para-substituted compounds (κ=ko/kp). For neighbouring-group activity
使用一组硫化物o-和p -XC 6 H 4 SMe,通过动力学方法研究了电子效应,空间位阻和TsNHCl加亲电Cl +和NalO 4进行O-转移的邻位助剂。通过比较邻位和对位取代的化合物的反应性(κ= k o / k p),评估了邻位取代基的空间效应和邻位助剂。对于邻居基团的活性,获得以下顺序:CH 2 OH〜CH 2OME〜CH 2 CO 2我