Síntese de 1-indanonas através da reação de acilação de Friedel-Crafts intramolecular utilizando NbCl5 como ácido de Lewis

Abstract

Recebido em 17/12/07; aceito em 27/2/08; publicado na web em 2/4/08 SYNTHESIS OF 1-INDANONES THROUGH THE INTRAMOLECULAR FRIEDEL-CRAFTS ACYLATION REACTION USING NbCl 5 AS LEWIS ACID. The intramolecular Friedel-Crafts acylation reaction of 3-arylpropanoic acids to give 1-indanones can be effected in good yields under mild conditions (room temperature) by using niobium pentachloride. Our results indicate that NbCl 5 acts both as reagent (to transform carboxylic acids into acyl chlorides) and as catalyst in the Friedel-Crafts cyclization.

Uma Eficiente Síntese De Derivados De Triarilmetano

“…Um exemplo dessas reações é a síntese de derivados do 4-aril-3,4-di-hidrocumarinas através da reação multicomponente entre 3,5-dimetoxifenol, malonato de dimetila e diferentes aldeídos aromáticos, na presença de pentacloreto de nióbio como ácido de Lewis (Dos SANTOS e Da SILVA-FILHO, 2012), conforme mostrado na Figura1. Outro exemplo é a síntese de derivados da 1-indanona, utilizando o NbCl5 como ácido de Lewis em reações de acilação de Friedel-Crafts intramolecular de ácidos 3-arilpropanóicos (POLO et al, 2008)…”

Organic Synthesis: New Vistas in the Brazilian Landscape

“…Brazil holds 86% of the world niobium reserves and this is one of the reasons why this metal became popular around here. Niobium(V) pentachloride has been employed as a very efficient Lewis acid in esterification reactions (de Sairre et al 2005, Aranda et al 2009, Diels-Alder (Constantino et al 2006), intramolecular Friedel-Crafts (Polo et al 2008), multicomponent reactions (de Andrade et al 2015) and others (Lacerda et al 2012) ( Figure 15).…”

An Efficient and Green Synthesis of 1‐Indanone and 1‐Tetralone via Intramolecular Friedel–Crafts Acylation Reaction

“…[1,2] 1-Indanones and 1-tetralones are usually obtained by the intramolecular Friedel-Crafts acylation of 3-arylpropanoyl chloride and 4-arylbutanoyl chloride,r espectively,b yu sing strong Lewis acids. [3][4][5] However,t hese Lewis acids have to be used in more than stoichiometric amount, anda dditionally cannot be recycled after the usual aqueous work-up. [2] Besides, the acyl chlorides are not "green" acylating agentsb ecause their preparation from carboxylic acids generates corrosive byproducts, such as HCl and SO 2 .…”

“…However, the use of carboxylic acids traditionally requires the treatment with an excessofL ewis acid or Brønsted acid, which cannotbe recovered andr eused. [5,[7][8][9][10] Metal triflates are efficient and green catalysts for Friedel-Crafts acylation. [11][12][13][14][15][16][17][18][19][20][21][22] Recently, metal-triflate-catalyzed Friedel-Crafts acylation with carboxylic acids as the acylating reagents has been studied extensively.…”