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Beak, Peter Gross, Kathleen Bertini 2015-09-25T22:14:12Z 2015-09-25T22:14:12Z 10000-01-01 1997 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. Made available in DSpace on 2015-09-25T22:14:12Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9812602.pdf: 11685939 bytes, checksum: 8008a16c20c15d06ead8f45f36a4aedf (MD5) Previous issue date: 1997 Embargo set by: Seth Robbins for item 85659 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 265 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997. http://hdl.handle.net/2142/84378 (MiAaPQ)AAI9812602 eng Chemistry, Organic 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 text Chemistry Chemistry University of Illinois at Urbana-Champaign Dissertation Ph.D.