1,4-Addition of Lithium Diisopropylamide to Unsaturated Esters: Role of Rate-Limiting Deaggregation, Autocatalysis, Lithium Chloride Catalysis, and Other Mixed Aggregation Effects

Lithium diisopropylamide (LDA) in tetrahydrofuran at −78 °C undergoes 1,4-addition to an unsaturated ester via a rate-limiting deaggregation of LDA dimer followed by a post-rate-limiting reaction with the substrate. Muted autocatalysis is traced to a lithium enolate-mediated deaggregation of the LDA...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2010-11, Vol.132 (44), p.15610-15623
Main Authors: Ma, Yun, Hoepker, Alexander C, Gupta, Lekha, Faggin, Marc F, Collum, David B
Format: Article
Language:English
Subjects:
Catalysis
Esters - chemistry
Furans - chemistry
Kinetics
Lithium - chemistry
Lithium Chloride - chemistry
Molecular Structure
Propylamines - chemistry
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Summary:Lithium diisopropylamide (LDA) in tetrahydrofuran at −78 °C undergoes 1,4-addition to an unsaturated ester via a rate-limiting deaggregation of LDA dimer followed by a post-rate-limiting reaction with the substrate. Muted autocatalysis is traced to a lithium enolate-mediated deaggregation of the LDA dimer and the intervention of LDA−lithium enolate mixed aggregates displaying higher reactivities than LDA. Striking accelerations are elicited by
ISSN:0002-7863
1520-5126
DOI:10.1021/ja105855v