Synthesis of functionalized furo[2,3-b]pyridines via the Pd-catalyzed coupling of acetylenes to iodopyridones. Preparation of a key intermediate to a new HIV protease inhibitor L-754,394

Cross‐Coupling Reactions to sp Carbon Atoms

“…Linstrumelle has reported that stronger bases considerably increase yield and reaction rate when no CuI co-catalyst is used in the reaction [74] (Table 6-6). Another study describes the reaction rate decreasing in the order of BuNH 2 i Et 3 N i iPr 2 NH i Et 2 NH i K 2 CO 3 for the cross-coupling of trimethylsilylacetylene (TMSA) with iodopyridone 33 (Scheme 6-12) [75]. Brandsma describes better results using iPr 2 NH over piperidine and Et 3 N in other instances [1c].…”

Application of palladium complexes bearing acyclic amino(hydrazido)carbene ligands as catalysts for copper-free Sonogashira cross-coupling

“…Thus, palladium complexes with ADC ligands were successfully employed in Suzuki-Miyaura [5][6][7], Heck [3,4,7], Buchwald-Hartwig [3,4], and Sonogashira reactions [3,4,[7][8][9][10][11]. Among them, Sonogashira coupling is typically performed in the presence of a copper co-catalyst (that improves reaction efficiency but brings about the generation of undesired by-products) [12][13][14][15][16][17], although a few copper-free systems, that are free from above disadvantages, are also known. Those include pioneering reports by Dhudshia and Thadani [7] (catalyst loading: 1.5 mol%; product yields up to 91%; TONs up to 60), and by Luzyanin and Boyarskiy [10,11] (catalyst loading: 0.1 mol%; product yields up to 99%; TONs up to 3.7 Â 10 4 ).…”

Novel Rearrangement of 3‐Acylaminofuro[2,3‐b]pyridines into 3‐(oxazol‐4‐yl)pyridin‐2‐ones

“…Furo[2,3‐ b ]pyridines are rarely found in nature . However, some representatives of the heterocyclic system have shown anticonvulsant activity , activity against HIV , central nervous system disorders , skin diseases , and hyperglycemia .…”