Palladium and Brønsted Acid Co-Catalyzed Biginelli-like Multicomponent Reactions via in Situ-Generated Cyclic Enol Ether: Access to Spirofuran-hydropyrimidinones

Abstract

Alkynol served as an enolizable carbonyl equivalent to react with (thio)urea and aromatic aldehydes, furnishing a variety of spirofuran-hydropyrimidinone compounds in good yields and excellent diastereoselectivities. The one-pot multicomponent reactions were realized with co-catalysis of palladium chloride and trifluoroacetic acid through a Biginelli-like tandem reaction pathway.

An efficient synthesis of 4,5-diaryl-3,4-dihydropyrimidin-2(1H)-oneviaa cesium carbonate-promoted direct condensation of 1-aryl-2-propanone with 1,1′-(arylmethylene)diurea

“…31 (m, 2H), 7.30-7.26 (m, 2H), 7.18-7.14 (m, 2H), 7.11-7.06 (m, 2H), 5.13 (s, 1H), 1.73 (s, 3H) ppm. 13 C NMR (100 MHz, DMSO-d 6 ): d 152. 8, 143.0, 136.7, 131.8, 131.2, 130.9, 130.8, 128.7, 128.4, 128.1, 106.8, 58.5, 16.2 14-7.05 (m, 4H), 5.12 (s, 1H), 1.73 (s, 3H) ppm.…”

“…8, 143.0, 136.7, 131.8, 131.2, 130.9, 130.8, 128.7, 128.4, 128.1, 106.8, 58.5, 16.2 14-7.05 (m, 4H), 5.12 (s, 1H), 1.73 (s, 3H) ppm. 13 C NMR (100 MHz, DMSO-d 6 ): d 152. 8, 143.4, 136.7, 131.3, 131.2, 130.9, 130.8, 129.1, 128.1, 120.4, 106.7, 58.6, 16.2 5, 142.6, 136.2, 132.6, 131.3, 131.1, 131.0, 129.9, 129.5, 128.5, 128.1, 121.9, 106.3, 58.6, 16.1 8, 148.5, 136.6, 131.1, 131.0, 130.8, 128.1, 126.6, 125.3, 124.4, 107.4, 54.2, 16.3 ppm.…”

“…FTIR (KBr, neat): n 2926, 1721, 1491, 1262, 1093, 1014 , 1H), 7.78-7.72 (m, 2H), 7.47 (s, 1H), 7.33-7.30 (m, 2H), 7.30-7.26 (m, 2H), 7.11-7.06 (m, 2H), 5.24 (s, 1H), 1.73 (s, 3H) ppm. 13 C NMR (100 MHz, DMSO-d 6 ): d 152. 7, 149.3, 136.4, 132.6, 131.3, 131.2, 130.9, 128.2, 127.8, 118.8, 110.1, 106.2, 58.8, 16. 144.0, 137.0, 131.1, 130.7, 130.7, 128.5, 128.1, 127.3, 126.8, 107.1, 59.2, 16. 141.1, 137.1, 136.4, 131.1, 130.6, 130.5, 129.0, 128.1, 126.8, 107.2, 58.9, 20.7, 16. 5, 152.9, 137.1, 136.2, 131.1, 130.…”

“…Mp: 250.4-251.6 C. 1 H NMR (400 MHz, DMSO-d 6 ): d 8.58 (s,1H),1H),1H),1H),4H),7.36 (s,1H),7.15 (d,J ¼ 7.8 Hz,2H),7.07 (d,J ¼ 8.0 Hz,2H), 5.99 (s, 1H), 1.81 (s, 3H) ppm. 13 C NMR (100 MHz, DMSO-d 6 ): d 152. 7,148.0,144.0,138.7,136.9,133.7,131.1,131.0,130.6,130.4,128.6,128.1,127.9,126.0,125.9,125.6,123.6,106.8,16.3 ppm.…”

“…3,4 With more than one century of development, tremendous achievements have been made in the Biginelli reaction, especially in the eld of organic synthesis, medicinal chemistry, polymer chemistry, and material sciences. 4,5 In addition, the variants of the Biginelli reaction by using other active methylene compounds (or their equivalents), such as 1,3cyclohexanedione, 6 acetophenone, 7 1-tetralone, 8 b-oxodithioesters, 9 enaminone, 10 cyclopentanone, 11 alkyl aldehydes, 12 and alkynol, 13 to replace ethyl acetoacetate for accessing diverse 3,4-dihydropyrimidin-2(1H)-ones have also been reported. Normally, the Biginelli or Biginelli-like reaction should be performed under acidic conditions in the presence of protic or Lewis acid.…”