ARTICLE pubs.acs.org/JACS
Regioselective Lithium Diisopropylamide-Mediated Ortholithiation of 1-Chloro-3-(trifluoromethyl)benzene: Role of Autocatalysis, Lithium Chloride Catalysis, and Reversibility Alexander C. Hoepker, Lekha Gupta, Yun Ma, Marc F. Faggin, and David B. Collum* Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States
bS Supporting Information ABSTRACT: Ortholithiation of 1-chloro-3-(trifluoromethyl) benzene with lithium diisopropylamide (LDA) in tetrahydrofuran at 78 °C displays characteristics of reactions in which aggregation events are rate limiting. Metalation with lithium-chloride-free LDA involves a rate-limiting deaggregation via dimer-based transition structures. The post-rate-limiting proton transfers are suggested to involve highly solvated triple ions. Autocatalysis by the resulting aryllithiums or catalysis by traces (
