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Sequestered Alkyllithiums: Why Phenyllithium Alone is Suitable for Betaine‐Ylide Generation
Author(s) -
Wang Qian,
Deredas Dariusz,
Huynh Cyril,
Schlosser Manfred
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390061
Subject(s) - phenyllithium , betaine , ylide , alkoxide , chemistry , deprotonation , lithium (medication) , wittig reaction , adduct , bromide , medicinal chemistry , organic chemistry , catalysis , medicine , ion , endocrinology
The key step in the trans ‐selective modification of the Wittig reaction is the α ‐lithiation of the lithium bromide coordinated ylide–aldehyde adduct (the so‐called “ P ‐betaine”). Only phenyllithium effects this deprotonation rapidly and cleanly. Alkyllithiums (in particular, butyl‐, sec ‐butyl‐, and tert ‐butyllithium) react only sluggishly and incompletely, being tied up in very stable mixed aggregates with the lithium alkoxide part of the betaines.