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Struktur eines O, N ‐Ketenacetals: (1 RS , 8 SR , 10 SR , 4(15) Z )‐4‐äthyliden‐5‐oxa‐3‐azatricyclo [8.4.0.0 3,8 ]tetradecan
Author(s) -
Kümin Albin,
Maverick Emily,
Seiler Paul,
Vanier Noel,
Damm Lorenz,
Hobi Reinhard,
Dunitz Jack D.,
Eschenmoser Albert
Publication year - 1980
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19800630507
Subject(s) - chemistry , diastereomer , ketene , stereochemistry , acetal , allylic rearrangement , tetradecane , square pyramid , intramolecular force , bicyclic molecule , crystal structure , crystallography , medicinal chemistry , biochemistry , organic chemistry , catalysis
Structure of a O,N‐Keteneacetal: (1RS, 8SR, 10SR, 4(15)Z)‐4‐Ethylidene‐5‐oxa‐3‐azatricyclo [8.4.0.0 3,8 ]tetradecane Die C‐Atome der äthylidenseitenkette der Titelverbindung 1 sind als C(15) und C(16) (s. Fig. 1 ) statt systematisch als C(1′) und C(2′) gekennzeichnet. Verbindung 1 kann auch als kondensiertes heterocyclisches Ringsystem benannt werden: 1‐äthyliden‐perhydro[1,3]oxazixino‐[3,4‐ b ]isochinolin. Methods for the preparation of a series of model compounds which were required for stereochemical studies are described: the tricyclic O, N ‐keteneacetal 1 , the two diastereomeric bicyclic amino acids 7 and 10 (see Scheme 2 ), and the two diastereomeric conformationally fixed tetrahydro‐1,3‐oxazines (=1,3‐oxazixanes) 9 and 11 . An x‐ray analysis of racemic 1 reveals a quasi‐tetrahedral nitrogen pyramid of the O, N ‐ketene acetal grouping, and an almost perfect conformational analogy between the N ‐ and C ‐centered allylic positions at the double bond.