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Stereoselective Lateral Functionalization of Monosubstituted [2.2]Paracyclophanes by Directed ortho ‐Metalation−Homologous Anionic Fries Rearrangement
Author(s) -
Focken Thilo,
Hopf Henning,
Snieckus Victor,
Dix Ina,
Jones Peter G.
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200106)2001:12<2221::aid-ejoc2221>3.0.co;2-3
Subject(s) - fries rearrangement , chemistry , metalation , surface modification , stereoselectivity , stereochemistry , regioselectivity , medicinal chemistry , organic chemistry , catalysis
Two efficient routes have been developed for the lateral functionalization of monosubstituted [2.2]paracyclophanes. After protection of the ortho site of an O ‐([2.2]paracyclophanyl) diisopropylcarbamate, an anionic Fries rearrangement resulted in a substitution of the benzylic position to give syn ‐4‐hydroxy‐ N , N ‐diisopropyl‐5‐triethylsilyl‐2‐[2.2]paracyclophanecarboxamide ( 4b ) with a syn / anti diastereoselectivity of more than 99:1. An alternate route consisted of the direct functionalization of the lateral position of N ‐ tert ‐butyl‐4‐[2.2]paracyclophanecarboxamide ( 9 ) by directed metalation. The reaction was found to be highly stereoselective, with only the syn isomer 11 being formed.