Enantioselective Synthesis of Triarylmethanes by Chiral Imidodiphosphoric Acids Catalyzed Friedel–Crafts Reactions
摘要:
The first enantioselective synthesis of pyrrolyl-substituted triarylmethanes has been accomplished using a novel imidodiphosphoric acid catalyst, which is derived from two (R)BINOL frameworks with different 3,3'-substituents. This strategy was also expanded to the synthesis of bis(indolyl)-substituted triarylmethanes with high enantioselectivities, which could only be obtained with moderate ee values in previous reports. These two efficient Friedel-Crafts alkylation processes feature low catalyst loading, broad functional group compatibilities, and the potential to provide practical pathways for the synthesis of enantioenriched bioactive triarylmethanes.
An efficient and expedient approach for the synthesis of unsymmetrical 3,3′-Bis-indolylmethanes via silica gel-mediated Friedel-Craftsalkylation of 3-indolylmethanols with diverse indoles is described. The synthetic utility of this transformation was demonstrated by reusing silica gel up to 10 times without apparent loss of reactivity .
The catalytic direct dehydrative coupling of an alkene with an alcohol is one of the most straightforward and green strategies for the formation of Csp2−Csp2 bonds. However, previously reported studies have only dealt with achiral reactions. Here, we describe chiral Brønsted acid‐catalyzed direct catalyticasymmetric dehydrative coupling reactions of 3‐vinylindoles and 3‐indolylmethanols. Various structurally
Brønsted acid promoted C–C bond formation between indolylmethyl electrophiles and ketene dithioacetals: Diastereoselective synthesis of highly functionalized cyclopenta[b]indoles
作者:Santosh D. Jadhav、Tavinder Singh、Anand Singh
DOI:10.1016/j.tetlet.2020.152349
日期:2020.9
method for the construction of carbon–carbon bonds between α-substituted indolylmethyl electrophiles and ketene dithioacetals is described. This strategy was utilized to access 2,3-disubstituted cyclopenta[b]indoles via formal [3+2] cycloadditions. Readily available indolyl methanols and α-indolyl-α-amino carbonyl compounds serve as electrophiles upon activation by p-toluenesulfonic acid (PTSA) and react
描述了一种布朗斯台德酸促进的方法,用于在α取代的吲哚基甲基亲电子试剂和乙烯酮二硫缩醛之间建立碳-碳键。利用该策略通过正式的[3 + 2]环加成反应获得2,3-二取代的环戊[ b ]吲哚。现成的吲哚基甲醇和α-吲哚基-α-氨基羰基化合物经p活化后可作为亲电子试剂-甲苯磺酸(PTSA)与乙烯酮二硫缩醛反应,形成两个碳-碳键和一个具有出色的非对映选择性的五元环。采用结构相关的吲哚基前体以实现分子多样性的优势被关键的替代作用所突显,这些作用突出了机理上的差异并指导了反应的发展。
Formal Asymmetric Organocatalytic [3+2] Cyclization between Enecarbamates and 3-Indolylmethanols: Rapid Access to 3-Aminocyclopenta[<i>b</i>]indoles
作者:Clément Lebée、Antti O. Kataja、Florent Blanchard、Géraldine Masson
DOI:10.1002/chem.201500749
日期:2015.6.1
A highly enantio‐ and diastereoselective synthesis of 3‐aminocyclopenta[b]indoles has been developed through formal [3+2] cycloaddition reaction of enecarbamates and 3‐indolylmethanols. This transformation is catalyzed by a chiral phosphoric acid that achieves simultaneous activation of both partners of the cycloaddition. Mechanistic data are also presented that suggest that the reaction occurs through
通过氨基甲酸酯和3-吲哚基甲醇的正式[3 + 2]环加成反应,已开发出高度对映体和非对映体选择性的3-氨基环戊[ b ]吲哚。该转化由手性磷酸催化,该手性磷酸实现了环加成的两个配偶体的同时活化。还提供了机理数据,表明该反应通过逐步途径发生。
Fluorinated alcohol-mediated [4 + 3] cycloaddition reaction of indolyl alcohols with cyclopentadiene
+ 3] cycloadditionreaction of 3-indolylmethanols with cyclopentadiene in hexafluoroisopropanol (HFIP), which is catalyst-free and inexpensive, and offers mild reaction conditions, wide substrate scope and convenient workup. This methodology provides the first catalyst- and additive-free [4 + 3] cycloadditionreactions of indolyl alcohols, offering a green and efficient method for the synthesis of cyclohepta[b]indole
本文介绍了3-吲哚基甲醇与环戊二烯在六氟异丙醇(HFIP)中的高效[4 + 3]环加成反应,该反应无催化剂且价格低廉,并且提供了温和的反应条件,宽泛的底物范围和方便的后处理方法。该方法学提供了吲哚醇的第一个无催化剂和无添加剂的[4 + 3]环加成反应,为合成环庚[ b ]吲哚衍生物提供了一种绿色而有效的方法。