Rhenium- and Manganese-Catalyzed Synthesis of Aromatic Compounds from 1,3-Dicarbonyl Compounds and Alkynes

Abstract

We have succeeded in the development of three approaches to the synthesis of aromatic compounds from 1,3-dicarbonyl compounds and alkynes. The first approach is a manganese-catalyzed [2+2+2] cycloaddition between 1,3-dicarbonyl compounds, which have no substituents at the active methylene moiety, and terminal alkynes. This reaction proceeds with high regioselectivity when aryl acetylenes are employed as the alkyne component. The second approach is a rhenium- or manganese-catalyzed formal [2+1+2+1] cycloaddition between beta-keto esters and two kinds of alkynes. In this reaction, the aromatic compounds are obtained by the following reaction sequence: (1) insertion of the first alkyne into a carbon-carbon single bond of a beta-keto ester, (2) formation of 2-pyranones via intramolecular cyclization with the elimination of ethanol, and (3) Diels-Alder reaction between the formed 2-pyranone and the second alkyne. This reaction provides multisubstituted aromatic compounds in a regioselective manner. The third approach is a rhenium-catalyzed formal [2+2+1+1] cycloaddition reaction from two 1,3-diketones and one alkyne. In this reaction, the aromatic skeleton is constructed from three carbons of the first 1,3-diketone, two carbons of the alkyne, and one carbon of the second 1,3-diketone.

Synthesis and photophysical properties of novel multisubstituted benzene and naphthalene derivatives with high 2D-π-conjugation

“…Therefore, as catalyst system we used [ReBr(CO) 3 (THF)] 2 (2-3 mol%) with the addition of powdered molecular sieves. Naphthalene derivatives were obtained from 2-pyranone (which in fact is protected diene) in [4+2] DielsAlder reaction with in situ generated benzyne at 20°C [27,28]. In addition, our studies have also shown that the application in this case of one-pot reaction (i.e.…”

“…Multisubstituted benzene derivatives were obtained based on a combination of cycloaddition [2+1+2+1] and Diels-Alder reaction [4+2] [27,28]. In [2+1+2+1] cycloaddition reaction as b-keto ester we used ethyl 2-methylacetoacetate, ethyl 2-benzylacetoacetate or ethyl butyrylacetate and diphenylacetylene or 1,2-bis(2,2 0 -bith iophene-5-yl)acetylene as the alkyne substrate.…”

“…with CO 2 -extrusion) required milder conditions: 150°C [27][28][29] for benzene and even room temperature for the naphthalene derivatives synthesis [27][28][29]. Another advantage of the [2+1+2+1] cycloaddition reaction followed by the [4+2] Diels-Alders reaction in comparison with other types of cycloaddition reaction tandem's, is their high regioselectivity [27][28][29], easy functionalization of the substrates [30], as well as certain functional groups tolerance [27][28][29]. Tetra-substituted naphthalene derivatives can be prepared with the great success from in situ generated benzene (from 2-trimethylsilylphenyl triflate and cesium fluoride) [27,28].…”

“…Another advantage of the [2+1+2+1] cycloaddition reaction followed by the [4+2] Diels-Alders reaction in comparison with other types of cycloaddition reaction tandem's, is their high regioselectivity [27][28][29], easy functionalization of the substrates [30], as well as certain functional groups tolerance [27][28][29]. Tetra-substituted naphthalene derivatives can be prepared with the great success from in situ generated benzene (from 2-trimethylsilylphenyl triflate and cesium fluoride) [27,28]. Herein we reported the multi-substituted benzene and naphthalene derivatives synthesized based on this reactions tandem.…”

Development of Novel and Highly Efficient Methods to Construct Carbon–Carbon Bonds Using Group 7 Transition-Metal Catalysts

“…Treatment of a 1,3-diketone with an alkyne in the presence of a rhenium catalyst, [ReBr-(CO) 3 (thf )] 2 , gave a multisubstituted aromatic compound (Scheme 35). 50 The number of carbon atoms of the products is one more than that of a sum of the starting 1,3-diketone and alkyne. From 13 C labeling experiments and the positions of the substituents in the substrate and product, it can be determined that the aromatic compound was derived from two moles of the 1,3-diketone and one mole of the alkyne.…”