Asymmetric Hofmann Elimination. Synthesis and Hofmann Degradation of Asymmetric Tertiary Amines Containing an N-Cyclooctyl Group^1a

Abstract

The synthesis of a number of tertiary amines containing the N-cyclooctyl group is described. The quaternary bases derived from some of these amines were subjected to Hofmann elimination conditions. The yield of cyclooctene and ratio of cis:trans isomers were determined. When the other alkyl groups attached to the nitrogen atom were aliphatic, cyclooctene was formed in good yield with a preponderance of the trans isomer. The presence of N-benzyl and N-allyl groups on the nitrogen atom led to lower yields of cyclooctene and a predominance of the cis isomer.ofmann decomposition of fully resolved* N-n-butyl-H N-isobutyl-N-methylcyclooctylammonium hydroxide was found to give a 53 yield of cis-and optically active trans-cyclooctene in a 33 : 67 ratio. In the exploratory work in search of a quaternary base suited for the resolution and asymmetric Hofmann elimination described in the preceding paper,3 a number of tertiary amines containing the N-cyclooctyl group were synthesized; some were converted to the methiodides and subjected to the Hofmann elimination reaction. This paper describes the results of this exploratory work.The secondary amines required as intermediates were prepared in high yield from cyclooctanone and the appropriate primary amine through the Schiff's base. The preparations were effected in separate steps because the usual low-pressure4 and high-pressure5 one-step reductive alkylation procedures failed to give the desired amines.Tertiary amines 1 to 9 were prepared by acylation of the appropriate secondary amine with an acid chloride followed by reduction of the resulting amide with lithium aluminum hydride (eq 1). Tertiary amines 1. R'COCI 2. LiAIH,)

Carbon-13 nuclear magnetic resonance spectral properties of alkyl disulfides, thiolsulfinates, and thiolsulfonates

“…The 13C NMR chemical shift assignments were made by off-resonance decoupling techniques and by observation of the expected downfield shifts due to changes in the electronegativity of divalent sulfur upon oxidation to the sulfinyl and sulfonyl functions. 8 The carbons of interest are labeled as ß, y, y', , ', and d with respect to the lone-pair electrons or the oxygen substitu-ent^) on sulfur as described below. X, = X2 = lone pair electrons (disulfide) X, = X2 = oxygen atom (thiolsulfonate) X, = oxygen atom; X2 = lone pair electrons (thiolsulfinate) dso and 8so¡, Effects.…”