First Crystal Structure Analysis of an Aliphatic Carbocation—Stabilization of the 3,5,7-Trimethyl-1-adamantyl Cation by CC Hyperconjugation
✍ Scribed by Dr. Thomas Laube
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 256 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0044-8249
No coin nor oath required. For personal study only.
✦ Synopsis
forms beautiful single crystals."*] Sulfur and selenium also add to 1, giving the chalcogenides 7b and 7c, respectively. Table 1 gives spectroscopic data for 1 and 7. Moreover, an X-ray structure analysis is available for 7a."*l Other reactions often proceed in a complex manner-as observed for the vinyl derivative 2, R=Ph[']-since the propyne/allene isomerism allows several possible sites of attack. Thus, whereas the mild quaternization with iodomethane (in benzene at O0C) indeed gives the monophosphonium salt 8,["' the use of the reagent in excess leads, even at 20"C, to the totally unexpected formation of the butynylphosphonium salt 9.[I4l Presumably, ylidic intermediates play a role in the lengthening of the allene/propyne chain. The PhzP unit that is lost is found in the reaction mixture as [Ph2PMe2JI.