In this paper, unsymmetrical bis­(indolyl)­methane (BIM) and 3-alkylindole derivatives are smoothly synthesized from symmetrical BIMs with a variety of nucleophiles including heteroaromatic/aromatic compounds, allylsilane and alkynylsilane. FeCl3·6H2O is found to be a mild and highly effective catalyst for this nucleophilic substitution reaction in which N-methyl-2-phenylindole behaves as a good leaving group in the Csp3 –Csp2 bond cleavage reaction. The operational ease, nonexpensive and environmentally friendly catalyst, mild reaction conditions, broad functional group tolerance, and scalability of this reaction strategy are advantages of the present procedure.

A first and short total synthesis of the marine sponge 2,3′-bis­(indolyl)­ethylamine (2,3′-BIEA) alkaloid (±)-gelliusine E was performed in both a three-step divergent approach and a one-pot three-component approach with an overall yield of up to 58%. A key feature of the novel strategy is PTSA-catalyzed transindolylation of the readily synthesized 3,3′-BIEAs with tryptamine derivatives. The structure of the isolated natural product is revised as protonated (±)-gelliusine E (4′). By design, this modular route allows the rapid synthesis of other members of the 2,3′-BIEA family, for example, (±)-6,6′-bis-(debromo)-gelliusine F and analogues with step economy, operational simplicity, and reduced waste. Furthermore, their cytotoxicity in breast cancer cells was investigated.

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An expedient access to a series of nonsymmetrical bis(indolyl)methanes (BIMs) through transindolylation of readily available symmetrical 3,3′-BIMs with various indoles catalyzed by silica-supported sulfuric acid has been established. This approach not only provides a useful strategy for the synthesis of structurally diverse BIMs, but also provides examples of nucleophilic substitution of BIMs with aromatic and nonaromatic π-systems, leading to a library of indolyl-substituted tri- and diarylmethanes. Moreover, this method was successfully applied in the first total synthesis of the 2,3′-BIM alkaloid (±)-colletotryptin E in three steps with an overall yield of 46%. The features of this procedure include a metal-free process, an inexpensive and environmentally friendly catalyst, mild reaction conditions, broad functional-group tolerance, good yields, and gram-scalable preparations.

Enantioconvergent catalysis has the potential to convert different isomers of a starting material to a single highly enantioenriched product. Here we report a novel enantioselective double convergent 1,3-rearrangement/hydrogenation of allylic alcohols using an Ir-N,P catalyst. A variety of allylic alcohols, each consisting of a 1:1:1:1 mixture of four isomers, were converted to the corresponding tertiary alcohols with two contiguous stereogenic centers, in up to 99% ee and 99:1 d.r. DFT calculations, and control experiments suggest that the 1,3-rearrangement is the crucial stereodetermining element of the reaction.