108448-77-7Relevant articles and documents
14. Origin of Diastereoselectivity in the Thermal [4+2] Cycloadditions of Dienophiles Derived from Oppolzer's Sultams: Steric vs. Stereoelectronic Influences
Chapuis, Christian,De Saint Laumer, Jean-Yves,Marty, Maurus
, p. 146 - 172 (1997)
Comparative semi-empirical PM3 and ab initio STO 3-21G calculations on bornanesultam-derived dienophiles containing the structural moiety SO2-N-C(O)-X(α) = Y(β) suggest that, among the conformers of low energy, the thermodynamically less stable SO2/C(O)-syn,C(O)/X=Y-s-cis conformation is also reactive in terms of LUMO level and atomic coefficients, Furthermore, the X(α), Y(β) LUMO atomic coefficients are nonequivalent with respect to both X(α)-re and X(α)-si faces, and thus have, depending on the conformation, a matching or mismatching stereoelectronic influence with the co-operative steric effect. This dissymmetry is believed to result from the generalized anomeric effect of the N lone pair, itself anomerically stabilized and directed, in the absence of crucial steric interactions, by the pseudo-axial anti-periplanar S=O bond. Five N-acyl-substituted bornanesultams are discussed ((-)-1a: N-acryloyl, X=CH, Y=CH2; (-)-1b: N-crotonoyl, X=CH, Y=CHMe; (-)-1c: N,N'-fumaroyl, X=CH, Y=CH(C(O)-bornanesultam); 2a: N-glyoxyloyl, X=CH, Y=O; 2b: N-acylnitroso, X=N, Y=O). In this context, differences with toluenesultams 3 are pointed out. A previous report on N-(acylnitroso)-bornanesultam 2b is revisited, and the diastereoselectivity observed is shown to result from thermodynamic control.
Asymmetric multicomponent [C+NC+CC] synthesis of highly functionalized pyrrolidines catalyzed by silver(I)
Garner, Philip,Kaniskan, H. Uemit,Hu, Jieyu,Youngs, Wiley J.,Panzner, Matthew
, p. 3647 - 3650 (2007/10/03)
Highly functionalized pyrrolidines are obtained in a single chemical step via a mild, efficient, and selective Ag1-catalyzed asymmetric [C+NC+CC] coupling process. Oppolzer's camphorsultam enables the desired reaction cascade and provides a rel
Stereocontrolled 1,3-dipolar cycloadditions using Oppolzer's camphor sultam as the chiral auxiliary for carbonyl stabilized azomethine ylides
Garner, Philip,Dogan, ?zdemir,Youngs, Wiley J.,Kennedy, Vance O.,Protasiewicz, John,Zaniewski, Rebecca
, p. 71 - 85 (2007/10/03)
Two complementary approaches to substituted pyrrolidines via stereocontrolled 1,3-dipolar cycloaddition reactions of chiral azomethine ylides are described. In one approach, chiral azomethine ylides were generated by thermolysis of aziridine carboxylate sultams and trapped with a variety of dipolarophiles to give good yields of the corresponding cycloadducts. In the second approach, chiral azomethine ylides were generated from glycyl sultams by 'imine tautomerization' and trapped with dipolarophiles to give good yields of the corresponding cycloadducts.