Gross, Kathleen M. Bertini; Beak, Peter published the artcile< Complex-Induced Proximity Effects: The Effect of Varying Directing-Group Orientation on Carbamate-Directed Lithiation Reactions>, SDS of cas: 149518-50-3, the main research area is proximity effect complex induced; carbamate directed lithiation.
A series of selected bicyclic carbamates in which the range of accessible angles and distances between the carbonyl group and the proton removed in an α-lithiation reaction are structurally defined have been investigated. Oxazolidinones I (n = 1, 2; R = i-Pr, t-Bu) undergo stereoselective lithiation-substitution reactions to provide cis-II as the major diastereomers. Two series of competition experiments show that the conformationally restricted carbamates undergo lithiation via complexes more efficiently than Boc amines (e.g., N-Boc-pyrrolidine, N-Boc-piperidine). These results along with semiempirical calculations suggest that a small dihedral angle and a calculated distance of 2.78 Å between the carbamate carbonyl oxygen and the proton to be removed are favorable for a carbamate-directed lithiation. A series of tin-lithium exchange experiments indicate that the configurational stability of a carbamate-stabilized organolithium species may be enhanced by restrictive geometry.
Journal of the American Chemical Societypublished new progress about Chelation (and configurational stability of carbanion intermediate). 149518-50-3 belongs to class piperidines, and the molecular formula is C12H21NO4, SDS of cas: 149518-50-3.
Referemce:
Piperidine – Wikipedia,
Piperidine | C5H11N – PubChem