Yamada, Shinji published the artcileAsymmetric Acylation of sec-Alcohols with Twisted Amides Possessing Axial Chirality Induced by the Adjacent Asymmetric Center, Quality Control of 171877-39-7, the main research area is asym acylation secondary alc twisted amide axial chirality; desymmetrization meso diols twisted amide axial chirality.
This paper reports that axially chiral twisted amides serve as asym. acylating agents for sec-alcs. under neutral conditions. Kinetic resolution of various racemic sec-alcs. and desymmetrization of 1,2-, 1,3-, and 1,4-meso-diols were performed by using the twisted amides. The utility of this desymmetrization method was shown by the preparation of the synthetic intermediate for macrolide antibiotic nodusmicin and 18-deoxynargenicin. The stereoselectivity of the acylation reactions is significantly dependent on the bulkiness of both the acyl group and the C-4 substituent of the chiral auxiliary. When an amide possessing an imidazolyl group at C-4 was employed, the stereoselectivity was reversed to give R esters. A possible working model of the acylation reaction is also described on the basis of the structural studies of the twisted amides by IR and 1H and 13C NMR spectroscopies and AM1 calculations These studies suggested a rotamer that is thermodynamically more stable than the others. This rotamer has an axial chirality about its C(O)-N linkage that is induced by the adjacent chiral center. This would enable discrimination of the two enantiomeric hydroxy groups of the racemic alcs. or meso-diols.
Journal of Organic Chemistry published new progress about Absolute configuration. 171877-39-7 belongs to class thiazole, name is (S)-4-Benzylthiazolidine-2-thione, and the molecular formula is C10H11NS2, Quality Control of 171877-39-7.
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica