Chromium(0)‐Catalyzed Tandem Cyclization of α,β‐Unsaturated Thioimidates Containing an Enyne Moiety

Synthesis of Azepine Derivatives by Rhodium‐Catalyzed Tandem 2,3‐Rearrangement/Heterocyclization

“…The present method can be employed to synthesize azepine derivatives, which are an important class of biologically active molecules, in an efficient manner. [16,17] Experimental Section Standard reaction conditions: 1,4-dioxane (0.2 mL) was added to a mixture of [{RhCl(cod)} 2 ] (4.9 mg, 0.01 mmol) and tppms (26.2 mg, 0.072 mmol) in a vial under an argon atmosphere and then stirred at 100 8C for 1.5 h. (Z)-1 a (0.4 mmol) in 1,4-dioxane (1.8 mL) was then added to this solution. The resulting mixture was stirred at 80 8C for …”

Divergent Synthesis of Highly Substituted Pyridines and Benzenes from Dienals, Alkynes, and Sulfonyl Azides

“…We reasoned that this assumption would provide a great opportunity to realize the divergent synthesis of skeletally different pyridines and benzenes. In consideration of the importance of pyridines and benzenes, we conceived a multicomponent cascade reaction comprised of the following: (1) the Cu-catalyzed reaction of an alkyne with an azide to produce 1,2,3-triazole, (2) the Rh-catalyzed reaction of a dienal with 1,2,3-triazole to generate oxazoline, (3) a thermal ring-opening or 8π-ring-closing reaction to afford azepine, and (4) a tunable 6π-ring-contracting reaction to provide a highly substituted pyridine or benzene. At the beginning of this research, it was not clear whether a competitive oxidation reaction of the CC double bond would occur in the formation of azepine II .…”

Transition metal-free, chemoselective arylation of thioamides yielding aryl thioimidates orN-aryl thioamides

“…7,24 This is in accordance with alkylations of thioamides, which have been reported to proceed with S-functionalization. 25 Based on these initial promising results, an extensive optimization was performed. 21 A solvent screening with LiOtBu as base revealed that EtOAc, iPrOAc and CH 2 Cl 2 gave comparable yields to reactions in toluene.…”