53617-66-6Relevant academic research and scientific papers
Synthesis, structure, and reactivity of (triphenylarsoranylidene)-methylcyclohepta-2,4,6-trienone derivatives: Reactions with heterocumulenes and an activated acetylene
Mitsumoto, Yuhki,Nitta, Makoto
, p. 2268 - 2274 (2002)
Stable arsonium ylide derivatives 7a,b bearing cyclohepta-2,4,6-trienyl and electron-withdrawing CO2Et and CN groups, respectively, have been prepared for the first time through a reaction of 2-chlorocyclohepta-2,4,6-trienone with the corresponding arsonium methylide derivatives in the presence of ButOK. Compounds 7a,b are isolated as stable crystalline compounds, which do not undergo hydrolysis even in acidic conditions. The X-ray crystal analysis revealed that their As-O bond distances (2.31 A for 7a, 2.39 A for 7b) lie below the sum of the van der Waals radii (3.37 A), and thus, there is appreciable bonding interaction between the arsenic and the oxygen elements. With a view to constructing a series of cyclohepta-annulated heterocycles and in order to gain a better understanding of a series of arsonium ylides, 7a,b were allowed to react with heterocumulenes such as carbon disulfide, phenyl isothiocyanate, diphenylcarbodiimido, and phenyl isocyanate, in a Wittig type reaction followed by electrocyclization or a formal [8 + 2]-type cycloaddition eliminating triphenylarsine sulfide or oxide to give 2H-cyclohepta[b]furan-2-thione, its imine, 2-phenylimino-2H-cyclohepta[b]pyrrole, and 2H-cyclohepta[b]furan-2-one. On the other hand, the reactions of 7a,b with dimethyl acetylenedicarboxylate (DMAD) give azulene derivatives.
Reaction of 2,2,2-Triphenyl-2H-6,11-methanocycloundec-1,2λ5-oxaphosphole (2-Triphenylphosphoranylidenemethyl-5,10-methanoannulenone) and Its Related Compounds with Heterocumulenes
Nitta, Makoto,Naya, Shin-ichi
, p. 2363 - 2380 (2007/10/03)
Reactions of 2,2,2-triphenyl-2H-6,11-methanocycloundec-1,2λ5-oxaphosphole annulenone> 8 and 2-(triphenyl-phosphoranylidenemethyl)tropones 9a-c with heterocumulenes have been studied to provide evidence for a P---O bonding betaine and to explore a preparative method for annulated heterocycles. The reaction of 8 with phenyl isocyanate 2 afforded N-phenyl-2H-6,11-methanocycloundecapyrrol-2-one in good yield, while that with phenyl isothiocyanate 4 afforded N-phenyl-2H-6,11-methanocycloundecapyrrol-2-thione and 2-(N-phenylamino)-4H-6,11-methanocycloundecathiophen-4-one in good combined yield. On the other hand, the reaction of 2-triphenylphosphoranylidenemethyltropone 9a, its ethoxycarbonyl- and cyano-substituted derivatives 9b,c with the isocyanate 2 gave 2H-cycloheptafuran-2-ones along with N-phenyl-2H-cycloheptafuran-2-imines, which are obtained by the reaction of compounds 9a,b with diphenylcarbodiimide 3. On the other hand, the reaction of compound 9a with the isothiocyanate 4 afforded 2-(N-phenylamino)-4H-cycloheptathiophen-4-one in addition to N-phenyl-2H-cycloheptafuran-2-imine, while compounds 9b,c reacted with the isothiocyanate 4 to give 2H-cycloheptafuran-2-thiones along with N-phenyl-2H-cycloheptafuran-2-imines. The reaction pathways and the important behavior of a P---O bonding structure for 8, as compared to that for 9a-c, are discussed on the basis of the 31P NMR spectral data and product analyses.
