Chiral Brønsted acid catalyzed Friedel-Crafts alkylation reactions

Pd-catalyzed asymmetric allylic alkylations of 3-substituted indoles using chiral P/olefin ligands

A palladium-catalyzed asymmetric allylic alkylation of 3-substituted indoles using P/olefin ligands was successfully achieved to afford a variety of indolenines containing a quaternary carbon stereocenter in high yields with up to 87% ee. Significantly, this reaction provides a concise access to a stereoisomer of the natural product Angelicastigmin.

Asymmetric one-pot sequential Friedel-Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme

In the presence of a peptide catalyst and the oxidative enzyme laccase, a one-pot sequential reaction including a Friedel–Crafts-type alkylation of α,β-unsaturated aldehydes followed by an α-oxyamination was realized. The reaction in aqueous solvent to promote the enzymatic oxidation, and the use of a peptide catalyst compatible with such conditions, were essential. The present sequential reaction afforded oxygen-functionalized indole or pyrrole derivatives in a highly enantioselective manner.

C-H activation: a complementary tool in the total synthesis of complex natural products

The recent advent of transition-metal mediated C-H activation is revolutionizing the synthetic field and gradually infusing a "C-H activation mind-set" in both students and practitioners of organic synthesis. As a powerful testament of this emerging synthetic tool, applications of C-H activation in the context of total synthesis of complex natural products are beginning to blossom. Herein, recently completed total syntheses showcasing creative and ingenious incorporation of C-H activation as a strategic manoeuver are compared with their "non-C-H activation" counterparts, illuminating a new paradigm in strategic synthetic design.

Asymmetric synthesis of the carbon-14-labeled selective glucocorticoid receptor modulator using cinchona alkaloid catalyzed addition of 6-bromoindole to ethyl trifluoropyruvate

We describe in this study the asymmetric synthesis of radioisotope (RI)-labeled selective glucocorticoid receptor modulator. This synthesis is based on optimization of the cinchona alkaloid catalyzed addition of 6-bromoindole to ethyl trifluoropyruvate and Negishi coupling of zinc cyanide to the 6-bromoindole moiety. [¹⁴C] Labeled (-)-{4-[(1-{2-[6-cyano-1-(cyclohexylmethyl)-1H-indol-3-yl]-3,3,3-trifluoro-2-hydroxypropyl}piperidin-4-yl)oxy]-3-methoxyphenyl}acetic acid (-)-1 was synthesized successfully with high enantioselectivity (>99% ee) and sufficient radiochemical purity.