Asymmetric organocatalytic synthesis of 4,6-bis(1H-indole-3-yl)-piperidine-2 carboxylatesElectronic supplementary information (ESI) available: Experimental details, analytic data (including NMR spectra, HPLC traces), details of CD spectral calculations, and crystallographic data for 9aa. CCDC 977608. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c4ob00234b

We developed an asymmetric organocatalytic synthesis of 4,6-bis(1 H -indole-3-yl)-piperidine-2-carboxylates using 10 mol% of a chiral phosphoric acid. The products, which are novel bisindole-piperidine-amino acid hybrids, can be obtained in one step from 3-vinyl indoles with imino esters in dichloromethane at room temperature after 1 h of reaction time. A variety of these compounds could be synthesized in up to 70% yield and 99% ee, and they were experimentally and computationally analyzed regarding their relative and absolute stereochemistry. An asymmetric synthesis of novel bisindole-piperidine-amino acid hybrids is reported, leading to products with good yields and excellent ees.