Convenient synthesis of 2-(1-adamantyl)furans.

There are several methods for the synthesis of 2-(1-adamantyl)furans, including those based on 1-adamantoyl chloride and malonic ester; 5-nitrofuran-2-carboxylic acid and 1-adamantanecarboxylic acid; 1-adamantylcarbaldehyde and propargylmagnesium bromide; 1-iodoadmantane and 2-acetylfuran. However, the disadvantages of the above methods for the synthesis of 1-adamantylated furans are the multistage synthesis schemes, in some cases the use of expensive palladium catalysts and specific reaction media or the formation of a mixture of reaction products. In addition, none of the methods is not implemented on a wide range of furan substrates, which would allow us to speak about the universality of the method. Therefore, we have developed a simple method of obtaining 2-(1-adamantyl)furans using a smaller amount of catalyst, providing a higher yield of the target products, as well as the possibility of varying the substituents in the furan ring. The result is achieved by the adamantylation of furans with 1-adamantanol in a nitromethane medium in the presence of a Lewis acid, for which aluminum or bismuth triflate was used in an amount of 10 mol%. Depending on the nature of the substituent in the furan ring, the reaction is carried out at room temperature or heated at 50-80 ° C. The method is applicable to a number of alkyl-, arylfurans, as well as to furans containing functional groups, such as carbethoxy, β-nitrovinyl, which are most promising for use in the synthesis of biologically active substances.