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

265 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997.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.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD