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Reaction of Organolithium Compounds with Alkali Metal Alkoxides – A Route to Superbases
Author(s) -
Lochmann Lubomír
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200006)2000:6<1115::aid-ejic1115>3.0.co;2-k
Subject(s) - chemistry , alkali metal , superbase , lithium (medication) , alkoxide , organolithium compounds , electrophile , organic chemistry , metal , inorganic chemistry , reactivity (psychology) , group 2 organometallic chemistry , catalysis , molecule , medicine , ion , alternative medicine , pathology , deprotonation , endocrinology
Organolithium compounds and lithium alkoxides form adducts, the reactivities of which are similar to those of the parent organolithium compounds. On the other hand, with heavy alkali metal alkoxides a metal interchange takes place, which gives rise to heavy alkali metal organic compounds. This is accompanied by a dramatic increase in the reactivity of the system, hence the name “Superbase” (SB) may be applied. This metal interchange is a general reaction and proceeds not only with organolithium compounds but also with lithium amides and lithium enolates of ketones and esters. SBs readily react with organic substrates to give heavy alkali metal derivatives of the substrate. Such reactions, followed by conversion with an electrophile, find wide application in organic synthesis. The properties of SBs may be further enhanced by using a greater than equimolar amount of a highly‐branched heavy alkali metal alkoxide (R 2 OM). In this review, the mechanism of SB reactions with substrates is discussed and the stoichiometric participation rather than catalytic effect of R 2 OM is documented. Although various routes for the reaction of SBs with substrates may be envisaged, a heavy alkali metal organic compound is involved in all cases.