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Selective Reactions, Resolution and Absolute Configuration of Bridged Hydroazulenes
Author(s) -
Tochtermann Werner,
Panitzsch Torsten,
Petroll Melanie,
Habeck Thorsten,
Schlenger Axel,
Wolff Christian,
Peters EvaMaria,
Peters Karl,
von Schnering Hans Georg
Publication year - 1998
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/(sici)1099-0690(199811)1998:11<2651::aid-ejoc2651>3.0.co;2-s
Subject(s) - chemistry , absolute configuration , sodium methoxide , regioselectivity , cyclopropanation , stereoselectivity , derivative (finance) , resolution (logic) , salt (chemistry) , stereochemistry , fractional crystallization (geology) , organic chemistry , catalysis , geochemistry , artificial intelligence , basalt , computer science , financial economics , economics , geology
Treatment of the bridged oxepine (±)‐1 with a large excess of powdered sodium methoxide in Et 2 O or with triphenylphosphonium methylide leads to the functionalized hydroazulenes (±)‐2 (69%) and (±)‐3 (81%). Regioselective and stereoselective cyclopropanation of (±)‐2 leads to the dibromocyclopropane derivative (±)‐4 . Epoxidation gives the epoxides (±)‐5 and (±)‐6 . The resolution of the hydro‐azulenone (±)‐2 is achieved by fractional crystallization of the quinine salt (–)‐8 of the corresponding mono acid (±)‐7 . The absolute configuration of (+)‐7 is established by X‐ray analysis of the quinine salt (–)‐8 .