Direct Olefination at the C-4 Position of Tryptophan via C–H Activation: Application to Biomimetic Synthesis of Clavicipitic Acid

A concise gram-scale synthesis of ht-13-A via a rhodium-catalyzed intramolecular C–H activation reaction

The enantioselective total synthesis of the 3,4-fused indole alkaloid ht-13-A has been achieved.

Palladium(ii)-catalyzed Sequential ortho-olefination of β-arylethamines with assistance of oxalyl amide

Pd-catalyzed highly selective ortho-alkenylation of β-arylethamines with the assistance of oxalyl amide is developed.

Palladium-catalyzed C-7 alkenylation of indolines using molecular oxygen as the sole oxidant

A general and efficient palladium-catalyzed C-7 alkenylation of indolines using molecular oxygen as the sole oxidant has been described.

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

This review summarizes the isolation, structure determination, total syntheses and biological activities of simple indole alkaloids and those with a nonrearranged monoterpenoid unit, with literature coverage from 2012 to 2013.

C7-derivatization of C3-alkylindoles including tryptophans and tryptamines

A versatile strategy for C7-selective boronation of tryptophans, tryptamines, and 3-alkylindoles by way of a single-pot C2/C7-diboronation-C2-protodeboronation sequence is described. The combination of a mild iridium-catalyzed C2/C7-diboronation followed by an in situ palladium-catalyzed C2-protodeboronation allows efficient entry to valuable C7-boroindoles that enable further C7-derivatization. The versatility of the chemistry is highlighted by the gram-scale synthesis of C7-boronated N-Boc-L-tryptophan methyl ester and the rapid synthesis of C7-halo, C7-hydroxy, and C7-aryl tryptophan derivatives.

Rhodium-catalyzed intramolecular annulation via C–H activation leading to fused tricyclic indole scaffolds

A new method for the synthesis of fused tricyclic indoles via a rhodium catalyzed intramolecular C–H activation reaction is described.

Selective C-2 alkylation of tryptophan by a Pd(II)/norbornene-promoted C-H activation reaction

A palladium(II)-catalyzed norbornene-mediated regioselective alkylation at the C-2 indole position of N-tert-butyloxycarbonyl (Boc)-protected (S)-tryptophan ethyl ester is reported. The protocol employs mild reaction conditions and is tolerant of a range of functional groups. The reaction proceeds without racemization at the stereogenic center of the amino acid.