1 -Pheny lethylamine

Reductive cathodic amination of 2,5-hexanedione with ammonia and 1-pheny-lethylamine at the Hg cathode gave 2,5-dimethylpyrrolidines with satisfactory yields and excellent cis selectivity (90-98%). Other amines reacted less selectively to afford mixtures of pyrroles and diastereoisomeric pyrrolidines. A mechanism is proposed that involves the reduction of iminium ions, in which the stereoselectivity is controlled after the two le reductions of the cyclic iminium ion by the final protonation [350]. 

P-Hydroxy carboxylic acids (12,3).2 This acetate on double deprotonation with LDA undergoes diastereoselective aldol reactions with aldehydes. The adducts are easily hydrolyzed to optically active P-hydroxycarboxylic acids with release of (R)-(+)-1,1,2-triphenyl-1,2-ethanediol, the precursor to 1. Optically pure acids can be obtained by crystallization of the salt with an optically active amine such as (S)-(—)-1 -pheny lethylamine. 

Enantiodifferentiating photocyclizations of prochiral 18a-e in zeolites modified with ephedrine, norephedrine, pseudoephedrine, menthol, and 1-pheny lethylamine gave 19a-e in moderate ees of up to 44% (obtained for 18a ill (— )-norephedrine-immobilized NaY). Diastereodifferentiating photocyclizations... 

As part of a programme designed to produce compounds with axial chirality, double Bischler-Napieralski reactions were carried out with oxamide derivatives of co-arylalkylamines. Thus, treatment of the oxamide derived from 3,4-dimethoxy- P -pheny lethylamine with pyrophosphoryl chloride in acetonitrile gave 1 in 84% yield, as expected. An attempt was then made to extend this double cyclisation protocol to the oxamide derived from 2-(3-methoxyphenoxy)ethylamine. Reaction of this latter compound under the same conditions used for the formation of 1, however, gave 2 in 81% yield instead of the expected product of a double Bischler-Napieralski reaction. 

Production of (S)-phenylethylamine by -selective methoxyacetylation of racemic pheny-lethylamine with lipase from Burkholderia plantari or Pseudomonas sp. in MTBE (BASF, 100-ton scale) [179]. 

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