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Stereoselective Synthesis of Annelated Piperidines by Photochemical Cycloaddition and Iminium IonAllylsilane Cyclization
Author(s) -
Tietze Lutz F.,
Wünsch Josef R.
Publication year - 1991
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199116971
Subject(s) - iminium , cycloaddition , chemistry , diastereomer , enamine , stereoselectivity , medicinal chemistry , ion , stereochemistry , organic chemistry , catalysis
Only one of eight possible diastereomers is produced on treatment of enamine carbaldehydes 1 (RH, CH 3 , p ‐MeOC 6 H 5 CH 2 ) with alkenes 2 ( n = 1, 2) that contain electron acceptor and allylsilane groups. A photochemical cycloaddition yields the 2‐hydroxytetrahydropyridine 3 , which cyclizes on addition of acids to the azabicycles 4. In the iminium ion intermediate stage, the allylsilane group attacks C2 anti to the H atom bound to C3.