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Precursors to the cyclo(n)carbons: From 3,4-dialkynyl-3-cyclobutene-1,2-diones and 3,4-dialkynyl-3-cyclobutene-1,2-diols to cyclobutenodehydroannulenes and higher oxides of carbon

Journal Article · · Journal of the American Chemical Society; (USA)
DOI:https://doi.org/10.1021/ja00160a047· OSTI ID:6728394
; ;  [1]
  1. Univ. of California, Los Angeles (USA)

A series of novel cyclobutenodehydro(n)annulenes (n = 18, 24, 30) have been prepared as precursors in an organic approach to the cyclocarbons C{sub 18}, C{sub 24}, and C{sub 30}. On the way to these macrocycles, synthetic entries to three new classes of enediynes have been developed. Bis(1-propynyl)cyclopropenone was prepared in the reaction of 1-(trimethylsilyl)-1-propyne with trichlorocyclopropenylium tetrachloroaluminate. The 3,4-dialkynyl-3-cyclobutene-1,2-dionines were prepared by the reaction of 3,4-dichloro-3-cyclobutene-1,2-dione either with (tri-n-butylstannyl)alkynes in the presence of catalytic amounts of Pd(PPh{sub 3}){sub 4} or with the soluble copper (I) acetylides of (trialkylsilyl)acetylenes. The peculiar downfield resonances of the terminal acetylenic carbon atoms in the {sup 13}C NMR spectra of the 3,4-dialkynyl-3-cyclobutene-1,2-diones are discussed. The oxidative Hay coupling of the acetonide of 3,4-diethynyl-3-cyclobutene-1,2-diol or of the bis(ethylene ketal) of 3,4-diethynyl-3-cyclobutene-1,2-dione gave two series of cyclobutenodehydroannulenes with 18{pi}-, 24{pi}-, and 30{pi}-electron perimeters.

OSTI ID:
6728394
Journal Information:
Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:4; ISSN 0002-7863; ISSN JACSA
Country of Publication:
United States
Language:
English