Epoxide organolithium reagents

Organolithium reagents react with epoxides in a similar manner... 

The reaction between Grignard reagents or organolithium reagents and epoxides is very valuable and is often used to increase the length of a carbon chain by two... 

Scheme 7.4 illustrates some of the important synthetic reactions in which organolithium reagents act as nucleophiles. The range of reactions includes S/v2-(ype alkylation (Entries 1 to 3), epoxide ring opening (Entry 4), and formation of alcohols by additions to aldehydes and ketones (Entries 5 to 10). Note that in Entry 2, alkylation takes place mainly at the 7-carbon of the allylic system. The ratio favoring 7-alkylation... 

A. Epoxide Ring Opening with Nonstabilized Organolithium Reagents... 

Electrocyclic rearrangements Organolithium reagents, 209 Elimination reactions to form carbon-carbon multiple bonds (see also Aromatization, Dehydrogenation, Deoxygenation of epoxides)... 

Few types of epoxide react with Grignard or organolithium reagents in the absence of catalysts without rearrangement. These include oxirane, which has been extensively used to transform these organometallic reagents into 2-substituted... 

Write equations for the reaction of organolithium reagents with water or epoxides. 

Alcohols can also be obtained from epoxides, aldehydes, ketones, esters, and acid chloride as a consequence of C-C bond formation. These reactions involve the addition of carbanion equivalents through the use of Grignard or organolithium reagents. 

Mechanism 14-4 Base-Catalyzed Opening of Epoxides 653 14-14 Orientation of Epoxide Ring Opening 654 14-15 Reactions of Epoxides with Grignard and Organolithium Reagents 656 14-16 Epoxy Resins The Advent of Modern Glues 656 Summary Reactions of Epoxides 658 EssentialTerms 660 Study Problems 662... 

Like other strong nucleophiles, Grignard and organolithium reagents attack epoxides to give (after protonation) ring-opened alcohols. 

The a-halo carbonyl compounds are reagents for the synthon +C-C=0. At a lower oxidation level, epoxides are reagents for the synthons +C-C=0 as in their reaction with Grignard or organolithium reagents (see also frames 162-6). 

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