ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Scope and Limitations of the Reductive Coupling of Aromatic Aldimine Derivatives with Formation of 1,2-Diarylethylenediamine Units, Using Low-Valent Titanium ReagentsBesides the adducts from lithium amides to aromatic aldehydes, iminium salts, animals, and N-silylimines of aromatic aldehydes are coupled by the black suspension obtained from TiCL4 and Mg turnings in tetrahydrofuran (THF). The 1,2-diarylethylenediamines with tertiary and primary amino groups thus obtained are formed with no or only moderate diastereoselectivity (products 4a-d (Scheme 2) and 5-e (Scheme 3), respectively); the amine component may contain a strained ring or additional heteroatoms as in azetidin, bis(2-methoxyethyl)amine, piperazine, morpholine, and thiomorpholine (products 6a-e; Table 1). By an in-situ procedure, ethylenediamines exclusively trans-diaryl-substituted piperazine and perhydro-1,4-diazepine derivatives (products 7a-f; Table 2). Enantiomerically pure monocyclic trans,cis-5-alkyl-2,-3-diaryl-piperazines and diazabicyclo[4.3.0]nonanes and -[4.4.0]decanes are obtained by employing suitable diamines prepared from the amino acids (S)-alanine, (S)-phenylalanine, (S)-proline and from (S,S)- or (R,R)-cyclohexane-1,2-diamine, respectively (products 11a-i, 7e; Table 4). The configuration of all products are derived from the high-field NMR spectra, some of which are discussed in detail (Figs. 1 and 2, Tables 3 and 5); all new compounds are fully characterized by their physical data. Depending upon the structure of the components employed, the yields of purified products range from as low as 7% to essentially quantitative.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19880710818
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