One-pot four-component synthesis of pyrimidyl and pyrazolyl substituted azulenes by glyoxylation–decarbonylative alkynylation–cyclocondensation sequences

• Charlotte F. Gers,
• Julia Rosellen,
• Eugen Merkul and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2011, 7, 1173–1181, doi:10.3762/bjoc.7.136

• Charlotte F. Gers Julia Rosellen Eugen Merkul Thomas J. J. Muller Institut für Organische Chemie und Makromolekulare Chemie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.7.136 Abstract A novel one-pot four-component synthesis of pyrimidyl

• one-pot four-component syntheses toward pyrimidyl- and pyrazolylazulenes. Results and Discussion Recently, we reported a three-component synthesis leading to the formation of ynones by a conceptually novel glyoxylation–decarbonylative Sonogashira coupling sequence (Scheme 2) [47]. The Lewis acid free

• relatively low yields were achieved. With this versatile three-component synthesis of azulenylynones in hand, the stage was set to expand the sequence to a four-component access to pyrimidyl- and pyrazolyl-substituted azulenes. Hence, the conditions for the terminating Michael addition–cyclocondensation step

Novel synthesis of pseudopeptides bearing a difluoromethyl group by Ugi reaction and desulfanylation

• Jingjing Wu,
• Hui Li and
• Song Cao

Beilstein J. Org. Chem. 2011, 7, 1070–1074, doi:10.3762/bjoc.7.123

• triglyceride transfer protein (MTP) and useful for the treatment of obesity and atherosclerosis (Figure 1) [20]. Among the protocols for the preparation of pseudopeptide derivatives, the Ugi four-component reaction offers significant advantages over conventional linear-step synthesis [21]. Various fluorinated

• building blocks have been used in the Ugi four-component reaction to construct a fluorinated compound library [22][23][24][25]. Our group has always been interested in developing efficient methods for the preparation of difluoromethyl-containing compounds through multicomponent reactions [26][27][28][29

Templated versus non-templated synthesis of benzo-21-crown-7 and the influence of substituents on its complexing properties

• Wei Jiang and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2010, 6, No. 14, doi:10.3762/bjoc.6.14

• construction of a four-component self-sorting system based on the fact that C7 cannot pass over a phenyl stopper group at the end of a dialkylammonium axle, while DB24C8 can [26]. This system was further extended to construct more complex multiply interlocked structures by using the strategy of integrative

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

Synthesis of dihydrophenanthridines by a sequence of Ugi-4CR and palladium- catalyzed intramolecular C-H functionalization

• Florence Bonnaterre,
• Michèle Bois-Choussy and
• Jieping Zhu

Beilstein J. Org. Chem. 2008, 4, No. 10, doi:10.3762/bjoc.4.10

• . Introduction Multicomponent reactions (MCRs) offer a unique way to generate efficiently libraries of complex molecules with high degree of diversity [1][2]. Among them, the Ugi four component reaction (Ugi-4CR) is without doubt one of the most powerful transformations that has been extensively investigated for

• Scheme 1. The Ugi four-component reaction between an o-iodobenzaldehyde 2, an aniline 3, an isocyanide 4 and a carboxylic acid 5 should afford an α-acetamido-α-phenylacetamide 6, which upon palladium-catalyzed C-H activation process should provide dihydrophenanthridine 1 [15][16][17][18][19][20][21

• temperature afforded the four-component adduct 6a (R1 = R2 = H, R3 = tert-butyl, R4 = n-propyl) in 84% yield. Cyclization of 6a was examined under a variety of conditions and the results are summarized in Table 1. Treatment of 6a under conditions we developed previously for the synthesis of tetracyclic