Synthetic Study of 4-Substituted Piperidine Ring in Elarofiban, RWJ-50042, Tirofiban and Paroxetine

A C-H oxidation approach for streamlining synthesis of chiral polyoxygenated motifs

Chiral oxygenated molecules are pervasive in natural products and medicinal agents; however, their chemical syntheses often necessitate numerous, wasteful steps involving functional group and oxidation state manipulations. Herein a strategy for synthesizing a readily diversifiable class of chiral building blocks, allylic alcohols, through sequential asymmetric C-H activation/resolution is evaluated against the state-of-the-art. The C-H oxidation routes' capacity to strategically introduce oxygen into a sequence and thereby minimize non-productive manipulations is demonstrated to effect significant decreases in overall step-count and increases in yield and synthetic flexibility.

Total syntheses of enantiomerically enriched R-(+)- and S-(–)-deplancheine

Total syntheses of indoloquinolizidine alkaloid (+/-)-, R-(+)-, and S-(-)-deplancheine are described here. The synthesis features an enantioselective intramolecular formal aza-[3 + 3] cycloaddition for the construction of the quinolizidine CD-ring. This application serves to introduce a new synthetic strategy for the synthesis of indoloquinolizidine alkaloids.

A facile route to polysubstitutedN-benzyl pyroglutamates

[reaction: see text] Base-induced coupling/cyclization reactions of alpha-sulfonylacetamide with various ethyl (Z)-2-bromo-2-propenoates have been carried out. The polysubstituted pyroglutamate carbon skeleton, with three contiguous asymmetric centers, was built up in one step. A ring-closure mechanism is proposed for the reactions.