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Ein neuartiger Einstieg in Wittig‐Umlagerungen – Eine stereoselektive [1,2]‐Wittig‐Umlagerung mit Konfigurationsumkehr am Carbanion‐Zentrum
Author(s) -
Hoffmann Rolf,
Brückner Reinhard
Publication year - 1992
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19921250824
Subject(s) - carbanion , wittig reaction , chemistry , stereoselectivity , stereochemistry , ether , bond cleavage , medicinal chemistry , catalysis , organic chemistry
A Novel Entry into Wittig Rearrangements – A Stereoselective [1,2]‐Wittig Rearrangement with Inversion of Configuration at the Carbanion Center The O,Se‐ketal 10 , through lithium naphthalenide induced reductive cleavage of its C sp 3–Se bond, was converted into the α‐lithio ether 11a with an equatorially oriented CO bond. At ‐78°C, 11a undergoes a rapid [1,2]‐Wittig rearrangement to provide stereoselectively the homoallylic alcohol 12a with an axial OH group. Thus, the rearrangement proceeds with inversion of configuration at the carbanion center.