Ein Verfahren zur Bestimmung von Zinn in zinnhaltigen Wolframerzen

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Reactions of P(MeNCH2CH2)3N with primary,secondary, and tertiary alkyl halides: Evidence for a solvent-enhanced dehydrohalogenation

The reactions of P(MeNCH₂CH₂)₃N, 1, with Mel, EtI, EtBr, n-PrBr, n-BuI, i-PrBr, PhCH₂CHBrCH₃, MeCHBr(CH₂)₄Me, s-BuBr, and t-BuBr were studied. The reactions of the primary alkyl halides produced the corresponding phosphonium cationic compounds, whereas the secondary and tertiary halides underwent elimination to form the corresponding olefins and the protonated form of 1. Based on ¹H and ¹³C NMR studies, it appears that elimination is exclusively trans, favoring the Saytzeff product. It was also observed that this reaction is enhanced by the solvent CH₃CN. The X-ray crystal structure of [Me(I)] I is also reported, featuring a transannular distance of 2.773 Å (2) facilitated by a rather wide average equatorial MeN-P-NMe bond angle of 113.1 (2)°. © 1996 John Wiley & Sons, Inc.