A two-step synthesis of spiro(2.4) hepta-1,4,6-triene 1 is described. The starting material 2 was synthesized by irradiation of diazocyclopentadiene in the presence of (2-bromovinyl)trimethylsilane. The predominant formation of the trans isomer probably reflects the isomeric composition of the starting alkene (cis:trans ratio $\approx$ 10:90). Elimination of 2 using CsF in dimethyl sulfoxide yielded 1.(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE MAI)
Spiro (2.4) hepta-1,4,6-triene is remarkably stable. $\rm\sp1H$ and $\rm\sp{13}C$ NMR data could be obtained at room temperature. The infrared spectrum exhibits a moderately strong absorption at 1713 $\rm cm\sp{-1}$ characteristic of cyclopropenes.
The ultraviolet spectrum of spiro (2.4) hepta-1,4,6-triene recorded in methanol has $\lambda\sb{\rm max}$ = 254 nm, very close to that reported (257 nm) for 3. This observation is in conflict with theoretical predictions which claim that 1 will experience a small hypsochromic shift resulting from spiroconjugation.(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE MAI)
| Identifer | oai:union.ndltd.org:RICE/oai:scholarship.rice.edu:1911/13840 |
| Date | January 1994 |
| Creators | Gutierrez, Molly Owers |
| Source Sets | Rice University |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | application/pdf |
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