Peri-interactions in naphthalenes, 2(1). Substituent effects in (8-dimethylamino-naphth-1-yl)- and [2-(dimethylamino-methyl)phenyl]-phosphines on the P-31-NMR signal positions

摘要

Contrary to claims in the literature, the P-31 NMR signal positions of ortho-dimethylaminomethyl-substituted triarylphosphines do not provide evidence for hypercoordination at phosphorus; the observed highfield shifts relative to triphenylphosphine are rather due to the ortho-effect. In (8-dimethylamino-naphth- 1-yl)phosphines, the signal positions similar to that of triphenylphosphine are the result of the highfield ortho-effect and a lowfield peri-substituent effect of about the same magnitude whose nature remains to be explored. [References: 91]