Catalytic Asymmetric Inverse-Electron Demand 1,3-Dipolar Cycloaddition of Isoquinolinium Methylides with Enecarbamates by a Chiral <i>N,N</i>′-Dioxide/Ag(I) Complex
The first catalyticasymmetricinverse-electrondemand [3 + 2]-cycloaddition of isoquinoliniummethylides with enecarbamates has been realized by using a N,N′-dioxide/Ag(I) complex. The optically active pyrroloisoquinolines and pyrrolophthalazine were obtained in up to 99% yield, >19:1 d.r., and 95% ee. On the basis of fluorescence, ESI-MS analysis, and X-ray structure of the product, a reasonable
Azomethine ylides such as 1 and 4 in which the nitrogen atom is incorporated in a six-membered heterocyclic ring undergo regiospecific [3+2] cycloadditions with the phosphaalkynes 2a and b at 130–140 °C to furnish the phosphaindolizines 3 and 5a–c after elimination of ethyl formate or hydrogen cyanide, respectively. In contrast, dipoles of the type 6 react unspecifically with the phosphaalkyne 2a to
Catalytic Asymmetric Syntheses of Quinolizidines by Dirhodium-Catalyzed Dearomatization of Isoquinolinium/Pyridinium Methylides–The Role of Catalyst and Carbene Source
作者:Xichen Xu、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1021/ja406482q
日期:2013.8.21
enantioenriched substituted quinolizidines has been achieved by chiraldirhodium(II) carboxylate-catalyzed dearomatizing formal [3 + 3]-cycloaddition of isoquinolinium/pyridinium methylides and enol diazoacetates. Coordination of Lewis basic methylides to dirhodium(II) prompts the rearrangement of the enol-carbene that is bound to dirhodium to produce a donor-acceptor cyclopropene. The donor-acceptor
The 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic Dicyanomethylides with Phenylsulfinylethene and Bis(trimethylsilyl)ethyne: Synthesis of 1,2-Unsubstituted 3-Cyanoindolizines
Pyridinium and diazinium dicyanomethylides underwent 1,3-dipolar cycloaddition-extrusion reactions with phenylsulfinylethene, producing the corresponding 3-cyanoindolizines in moderate to good yields. 1,3-Dipolar cycloadditions of these ylides with bis(trimethylsilyl)ethyne gave either the 1,2-bis(trimethylsilyl)-3-cyanoindolizines or the 1-trimethylsilyl-3-cyanoindolizines, or mixtures of these, depending
Cycloaddition reactions of cycloimmonium ylides with triphenylcyclopropene
作者:Kiyoshi Matsumoto、Takane Uchida
DOI:10.1039/p19810000073
日期:——
course of the reaction is discussed qualitatively. The pyrazinium dicyanomethylide (16) with TPP produces the 7-azaindolizine (19), whereas pyridazinium (17) and phthalazinium (18) dicyanomethylides give the primary adducts (20) and (21), respectively. Reaction of pyridinium bis(alkoxycarbonyl)methylides (22) with TPP gives, however, generally poor or no yield of the indolizines.