Search for Long-Lived 1,3-carbodications and Preparation of the Persistent 1,1,3,3-tetracyclopropyl-1,3-propanediyl Dication

Abstract

Several substituted versions of 1,3-propanediol were ionized under a variety of superacidic conditions, and the product carbocations and carboxonium species were characterized by 13C NMR spectroscopy at low temperatures. 1,1,3-Triphenyl-1,3-propanediol (19), and 1,1,3,3-tetraphenyl- 1,3-propanediol (20), upon ionization in FSO3H/SO2ClF or SbF5- FSO3H/SO2ClF solution at -78 °C gave the disproportionated cationic species, 1,1-diphenylethyl cation (24) and protonated benzaldehyde (25) or protonated benzophenone (26). At lower temperatures (-130 °C) they yielded the allyl cations, 29 and 30, as the only products. Diol 23 was also ionized at -78 °C to give a 1:1 mixture of tricyclopropylmethyl cation (27) and O- protonated dicyclopropyl ketone (28). The ionization of 1,1,3,3- tetracyclopropyl-1,3-propanediol (21) in SbF5/SO2ClF, on the other hand, gave the stable 1,3-carbodication, that is, 1,1,3,3-tetracyclopropyl-1,3- propanediyl dication (33). The structures and the 13C NMR chemical shifts for the carbodication 33 and the allyl cations 29 and 30 were also computed using DFT/IGLO methods.

Department(s)

Chemistry

Keywords and Phrases

1,3 propanediol; benzaldehyde; benzophenone; propanediol derivative; carbon nuclear magnetic resonance; chemical reaction; chemical structure; ionization

International Standard Serial Number (ISSN)

0002-7863

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1999 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Nov 1999

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