Synthetic and Mechanistic Studies of Carbamate-Directed Lithiation Reactions: (1) Assymetric Deprotonation of N-Boc Indolines. (2) the Relationship Between Reactivity and Directing Group Orientation

Gross, Kathleen Bertini

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Description

Title

Synthetic and Mechanistic Studies of Carbamate-Directed Lithiation Reactions: (1) Assymetric Deprotonation of N-Boc Indolines. (2) the Relationship Between Reactivity and Directing Group Orientation

Author(s)

Gross, Kathleen Bertini

Issue Date

1997

Doctoral Committee Chair(s)

Beak, Peter

Department of Study

Chemistry

Discipline

Chemistry

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Chemistry, Organic

Language

eng

Abstract

A series of tin-lithium exchange experiments indicate that rotationally restricted $\alpha$-lithio carbamates have increased configurational stability relative to more flexible analogs. An increase in the rate of epimerization of $\alpha$-lithio carbamates in the presence of $N,\ N,\ N\sp\prime ,\ N\sp\prime$-tetramethylethy lenediamine suggests that the rate-determining step for epimerization is the separation of the carbanionic carbon and the lithium. Chelation of the carbamate carbonyl oxygen to the lithium in $\alpha$-lithio carbamates appears to influence their thermodynamic stability. These studies demonstrate that the position of the carbonyl group with respect to the proton removed in a carbamate-directed lithiation affects the efficiency of the reaction as well as the configurational stability of the organolithium intermediate.

Graduation Semester

1997

Type of Resource

text

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