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 .
Construction of Novel Tetrahydro-<i>β</i>-carboline-1-thione Spirooxindoles by Brønsted Acid Mediated Formal [3+3] Cyclization of 3-Indolylmethanols with 3-Isothiocyanato Oxindoles
p‐Toluenesulfonic acid mediated formal [3+3] cyclization of 3‐indolylmethanols with 3‐isothiocyanato oxindoles was realized. This transformation allowed for the synthesis of a series of novel tetrahydro‐β‐carboline‐1‐thione spirooxindoles in moderate to excellent yields (up to 99%) with generally good diastereoselectivities (up to >20:1). The structure of one product was determined by an X‐ray crystal
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
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。