Electrophile-Directed Diastereoselective Oxonitrile Alkylations.

Diastereoselective alkylation of prochiral oxonitrile dianions with secondary alkyl halides efficiently installs two contiguous stereogenic centers. The confluence of nucleophilic trajectory and the electrophile chirality causes distinct steric differences that allow efficient discrimination for one of the six possible conformers. Numerous oxonitrile-derived dianions efficiently displace secondary alkyl halides propagating the electrophile chirality to efficiently install two contiguous tertiary centers.

Metalated nitrile and enolate chlorinations.

Metalated nitriles and enolates rapidly and efficiently abstract chlorine from 2-chloro-2-fluoro-2-phenylacetonitrile to afford a diverse range of chloronitriles and chloroesters. The method provides the first general anionic chlorination of alkylnitriles, tolerates numerous functional groups, and addresses the challenge of synthesizing alpha-chloronitriles under mild conditions.

Synthesis and biological evaluation of 4beta-[(4-substituted)-1,2,3-triazol-1-yl]podophyllotoxins as potential anticancer agents.

A series of novel 4beta-[(4-substituted)-1,2,3-triazol-1-yl]podophyllotoxin derivatives were synthesized by employing Cu(I)-catalyzed click chemistry and evaluated for their anticancer activity against a panel of seven human cancer cell lines (HT-29, HCT-15, 502713, HOP-62, A-549, MCF-7, and SF-295). The compounds 9b, 9c, 9e, 9f, and 9h showed significant cytotoxic activities especially against HT-29, HCT-15, 502713 cell lines.