4075-96-1

A number of tertiary sec-alkylamines (22 examples, 29-80% yield) have been prepared according to a simple one-pot procedure by the addition of Grignard reagents to N,N-dialkylformamides in the presence of Ti(OiPr)4 and Me3SiCl. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

A series of nine compounds consisting of dimethyl, trimethyl and ethyldimethyl ammonium bromides in which the other alkyl group contains a (2-phenyl)ethyl moiety were synthesised and studied by CP/MAS NMR. The results of dynamic NMR studies on the solids suggest that there is a dramatically wide range of molecular motions occurring in this simple series of compounds. A combination of dynamic line shape analyses and Τ1ρ measurements reveals the considerable extent of intramolecular group motions including rotations of trimethylammonium, ethyldimethylammonium and phenyl groups. Rates of rotation and activation parameters for these molecular motions are derived where appropriate.

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N-Alkyl-N-methyl(4-substituted benzyl)ammonium N-alkylides (3), produced by fluoride ion induced desilylation of N-alkyl-N-methyl-N-(4-substituted benzyl)-1-(trimethylsilyl)alkylammonium iodides (2), were mainly converted into N-alkyl-N-methyl-1-(4-substituted benzyl)alkylamines (5, Stevens rearrangement products) and 4-substituted toluenes (8).Both compounds were produced via radical-forming and -destroying pathways from 2-substituted-6--5-methylene-1,3-cylohexadienes (4), which were initially formed from 3 by sigmatropic rearrangement.There is no direct migration pathway from 3 to 5.

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Reactions of the positionally isomeric 1-phenyl-1-propyl (I) and 1-phenyl-2-propyltrimethylammonium (II) ions with CH3OK - CH3OH, t-C4H9OK - t-C4H9OH and t-C4H9OK - C6H6 systems have been investigated with aid of the deuterated analogues erythro-2-D-I, threo-2-D-I, 1-D-I and threo-1-D-II.At least five mechanistic components (anti-β-elimination, syn-β-elimination, α',β-elimination, Sommelet-Hauser rearrangement and SN2 substitution) have been found to participate in the reaction of the quaternary compound I, in proportions varying greatly with base-solvent combination.The corresponding reactions of the isomeric compound II proceeded in a more simple manner, withount the intervention of ylide pathways in the olefin as well as in the amine formation.The stereochemistry of β-elimination determined for the two phenyl-substituted 'onium compounds has been compared with that reported previously for structurally related aliphatic analogues.The "anomalously" low propensity for syn-elimination as well as the "anomalously" high values of trans/cis-olefin rations in anti-elimination stigmatizing the presence of phenyl substituents are proposed to originate from a lack of base-approach hindrance in the reaction.