Highly Enantioselective Insertion of Carbenoids into N-H Bonds Catalyzed by Copper(I) Complexes of Binol Derivatives
Highly Enantioselective Insertion of Carbenoids into N-H Bonds Catalyzed by Copper(I) Complexes of Binol Derivatives
复制标题
二元醇衍生物铜(I)配合物催化类胡萝卜素高度对映选择性插入N-H键
DOI：
10.1002/anie.201001686
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Feng, Xiaoming
中科院分区：
文献类型：
--
作者：
Hou, Zongrui;Wang, Jun;Feng, Xiaoming
研究了α-重氮羰基化合物在X = H键（X= C，N，P，O，S等）上的催化不对称插入反应.由于它提供了一种构造多功能和有用的积木的有效方法，因此引起了广泛的关注。[1]相对于不对称CNOH插入的广泛和富有成效的研究[2]，α-重氮羰基化合物对映选择性插入杂原子-氢键（XNOH）的研究仍然有限。[3]这可能是由于存在高反应性的极性X2 OH键，其在亲电金属卡宾攻击杂原子上的孤对电子时形成叶立德中间体，从而导致更复杂的络合物。[4]此外，起始胺和产物中的刘易斯碱性氮原子倾向于与催化剂中的中心金属原子强烈配位，这可能导致催化剂失活。[5]在这些插入反应中，金属催化的类卡宾NH 4 OH插入反应非常重要，因为它们导致形成各种生物活性分子，如α-氨基酮，α-氨基酸衍生物和药学上有用的化合物。[6]在一项开创性的研究中，Jørgensen及其同事报道了第一个通过手性铜（I）/银（I）双恶唑啉络合物进行的不对称分子间NH 4 OH插入反应。虽然只有低到中等的产率和ee值，这项研究实际上打开了大门，不对称版本的NH 4 OH插入反应。[7]直到Zhou和同事报道了使用由螺二恶唑啉配体、CuCl和NaBARF（BARF=[B [3，5-（CF 3）2C 6 H3] 4] Cl）组成的催化体系的优异ee值（98%）和产率（94%），才取得了进一步的突破。[8]后来，Lee和Fu公开了另一种以α-芳基重氮酯和氨基甲酸酯（Boc-NH 2和Cbz-NH 2; Boc=叔丁氧羰基，Cbz=苄氧羰基）为底物的高对映选择性NH 4 OH插入反应，该反应产生了具有优异ee值（高达94%）的有用的芳基甘氨酸衍生物。[9]尽管取得了这些成就，但鉴于这种NH 4 OH插入反应的巨大用途，仍然非常需要探索替代的有效催化体系。本文报道了一种新的、易得的铜（I）催化剂，以（R）-联苯二酚衍生物2b和CuCl为原料，以高产率和ee值合成了一系列对映体富集的取代α-氨基乙酸酯。最近，本研究组报道了一种新的轴向手性N，N '-二氧化物1，其被证明是用于N-Ts-保护的酮亚胺（Ts= 4-甲苯磺酰基;方案1）的对映选择性Strecker反应的高效有机催化剂。[10]为了发现该化合物的进一步用途，
The catalytic asymmetric insertion reaction of α-diazocarbonyl compounds into XÀH bonds (X= C, N, P, O, S, etc.) has attracted much attention because it provides an efficient way to construct versatile and useful building blocks.[1] In contrast to the extensive and fruitful studies on asymmetric CÀH insertion,[2] the investigation of enantioselective insertion of α-diazocarbonyl compounds into heteroatom–hydrogen bonds (XÀH) is still limited.[3] This may result from the presence of the highly reactive polar XÀH bonds, which form the ylide intermediates upon attack of the electrophilic metal carbene to the lone pair of electrons on the heteroatom, thus leading to a more intricate complexion.[4] Moreover, the Lewis basic nitrogen atoms in the starting amine and in the products tend to strongly coordinate to the central metal atom in the catalyst, which may result in the deactivation of the catalyst.[5] Among the insertion reactions, metal-catalyzed carbenoid NÀH insertions are of great importance, because they lead to the formation of various bioactive molecules such as α-amino ketones, α-amino acid derivatives, and pharmaceutically useful compounds.[6] In a pioneering study, Jørgensen and co-workers reported the first asymmetric intermolecular NÀH insertion reactions by means of chiral copper (I)/silver (I) bisoxazoline complexes. Although only low to moderate yields and ee values were obtained, this study has actually opened the doors to asymmetric versions of NÀH insertion reactions.[7] No further breakthrough was made until Zhou and co-workers reported excellent ee values (98%) and yields (94%) using a catalytic system consisting of a spirobisoxazoline ligand, CuCl, and NaBARF (BARF=[B [3, 5-(CF3) 2C6H3] 4] À).[8] Later, Lee and Fu disclosed another highly enantioselective NÀH insertion reaction with α-aryl diazoesters and carbamates (Boc-NH2 and Cbz-NH2; Boc= tert-butoxycarbonyl, Cbz= benzyloxycarbonyl) as substrates, which leads to useful arylglycine derivatives with excellent ee values (up to 94%).[9] Despite these achievements, in view of the great utility of this NÀH insertion reaction, the exploration of alternative efficient catalytic systems is still highly desirable. Herein, we describe a novel and readily available copper (I) catalyst generated from the (R)-binol derivative 2b and CuCl, from which a series of enantioenriched substituted α-amino acetates were prepared in excellent yields and ee values.Recently, our research group reported a novel axially chiral N, N’-dioxide 1, which was demonstrated to be a highly efficient organocatalyst for the enantioselective Strecker reaction of N-Ts-protected ketimines (Ts= 4-toluenesulfonyl; Scheme 1).[10] To find further uses for this compound,