描述了将硝基乙酸乙酯高度对映选择性地有机催化加至由芥末衍生的N-Boc酮亚胺(Boc =叔丁氧基羰基)中,然后除去硝基的方法。可扩展的反应序列导致标题化合物作为吡咯并吲哚啉生物碱和相关药物的重要中间体,具有优异的收率和对映选择性。已进行了六氢呋喃[2,3- b ]吲哚骨架,螺氨基甲酸酯和吲哚单元的合成,以及AG-041R的正式合成,以证明该方案的合成效用。
Catalytic Asymmetric Mannich Reaction of α-Fluoronitriles with Ketimines: Enantioselective and Diastereodivergent Construction of Vicinal Tetrasubstituted Stereocenters
作者:Ransheng Ding、Zeus A. De los Santos、Christian Wolf
DOI:10.1021/acscatal.8b05164
日期:2019.3.1
Diastereodivergent and enantioselective conversion of isatin ketimines to α-fluoro-β-aminonitriles with vicinaltetrasubstituted stereocenters is achieved by a chiral copper complex/guanidine base catalyzed Mannich reaction with proper choice of the bisphosphine ligand. The reaction is broad in scope, scalable, and provides efficient access to a series of 3-aminoindolinones exhibiting a quaternary
Phosphine-mediated Highly Enantioselective Spirocyclization with Ketimines as Substrates
作者:Xiaoyu Han、Wai-Lun Chan、Weijun Yao、Yongjiang Wang、Yixin Lu
DOI:10.1002/anie.201600453
日期:2016.5.23
Phosphine‐catalyzed enantioselectiveannulation reactions involving ketimines are a daunting synthetic challenge owing to the intrinsic low reactivity of ketimine substrates. A highly enantioselective [3+2] cycloaddition reaction that makes use of isatin‐derived ketimines as reaction partners was developed. Notably, both simple and γ‐substituted allenoates could be utilized, and various 3,2′‐pyrrolidinyl
Enantioselective construction of 3-substituted 3-amino-2-oxindoles containing an <i>N</i>,<i>N</i>-ketal skeleton <i>via</i> organocatalyzed aza-addition of isatin imines
作者:Chen Zhang、Xinye Shang、Yuyu Cheng、Fushuai Li、Hanhui Zhao、Pengfei Li、Wenjun Li
DOI:10.1039/c9ob01870k
日期:——
The first example of organocatalytic chemo-, regio- and enantioselective aza-Mannich reactions of triazoles and arylamines, respectively, with isatin-derived imines has been achieved.
A new class of chiral N-sulfonyl bisimidazoline (Bim) ligands have been designed, prepared, and applied in Pd(II)-catalyzed asymmetric addition of arylboronic acids to isatin-derived N-Boc ketimines. The combination of Pd(OCOCF3)2 and N-tosyl Bim ligand shows high catalytic activity and excellent asymmetric induction, enabling asymmetric addition to offer α-tertiary amines with generally good to high
Chiral Binaphthyl‐Based Iodonium Salt (Hypervalent Iodine(III)) as Hydrogen‐ and Halogen‐Bonding Bifunctional Catalyst: Insight into Abnormal Counteranion Effect and Asymmetric Synthesis of
<i>N</i>
,
<i>S</i>
‐Acetals
Asymmetric construction of chiral N,S-acetal skeletons is important because they are widely present in natural products and pharmaceuticals. Halogen-bonding is a unique interaction that has been an organic synthesis focus, although research into chiral variants is limited. Halonium salts have been found to act as halogen-bonding catalysts and asymmetric catalysis using chiral bromonium salts under basic
手性N,S-缩醛骨架的不对称结构很重要,因为它们广泛存在于天然产物和药物中。卤素键是一种独特的相互作用,一直是有机合成的焦点,尽管对手性变体的研究有限。已经发现卤盐作为卤素键合催化剂,我们小组最近发现了在碱性条件下使用手性溴盐的不对称催化。在此,我们报告了手性N、S的不对称合成通过在中性条件下由手性碘鎓盐催化的亚胺中添加大量硫醇,可产生良好至优异的产率和对映选择性(82-97% ee)。使用NMR实验和似是而非的中间体的DFT计算研究了反应机理,结果表明亚胺底物被催化剂以双齿方式活化。本系统中四[3,5-双(三氟甲基)苯基]硼酸根阴离子的异常抗衡阴离子效应通过1 H NMR 光谱检测。