| Popis: |
Proton noise decoupled 13C NMR spectra were recorded of 23 substituted allenes as neat liqs. at 25.16 MHz. Each Me, Et, and S-alkyl substituent contributed +3.3, +4.8, and +7 g 2 ppm, resp., to the 13Cb chem. shift (d) of R1R2Ca:Cb:CgR3R4. An approx. linear correlation was obsd. between dCb of monosubstituted allenes and dCb of the corresponding monosubstituted vinyl compds. XCaH:CbH2: the slope, .apprx.0.35, indicates that the vinyl C is more sensitive to the substituent effect than is the allenic Cb. For the monosubstituted allenes, dCb decreased approx. linearly with increasing dCg. [on SciFinder (R)] |
