1 Supporting Information Stereoselective synthesis of highly functionalized tetrahydrocarbazoles through a domino Michael-Henry reaction: an easy access of four contiguous chiral centers Pradeep Kumar Jaiswal, Soumen Biswas, Shivendra Singh, Biswarup Pathak, Shaikh M. Mobin and Sampak Samanta *, a 1. General information All reactions were carried out under air and monitored by TLC using Merck 60 F 254 pre coated silica gel plates (0.25 mm thickness) and the products were visualized by UV detection. Flash chromatography was carried out with silica gel (200-300 mesh). FT-IR spectra were recorded on a Bruker Tensor-27 spectrometer. 1 H and 13 C NMR spectra were recorded on a Bruker Avance (III) 400 MHz spectrometer. Data for 1 H NMR are reported as a chemical shift (δ ppm), multiplicity (s = singlet, d = doublet, q = quartet, m = multiplet), coupling constant J (Hz), integration, and assignment, data for 13 C are reported as a chemical shift. High resolutions mass spectral analyses (HRMS) were carried out using ESI-TOF-MS. HPLC analysis was performed on YL-9100 HPLC, UV detection monitored at appropriate wavelength respectively, using Chiralcel AD-H (0.46 cm x 25 cm) column. Materials: All β-nitrostyrenes and organocatalyst either synthesized by literature known procedure or purchased from commercial sources. General experimental procedure for the synthesis of highly functionalized tetrahydrocarbazole derivatives (entry 1-18, Table 2): To a stirred mixture of methyl 3-formyl-1H-indole-2-acetates 1 (1a-b, 0.20 mmol) and β-nitrostyrenes (2a-k, 0.25 mmol) in dry THF (1.0 mL) was added catalyst DABCO (10 mol%) at room temperature for 6-12h (monitored by TLC). After that, THF was evaporated by rotary evaporator under reduced pressure. The crude product was extracted with ethyl acetate, washed with water, dried over Na 2 SO 4 . The evaporation of the solvent left the crude product which was purified by column chromatography over silica-gel 230-400 mesh using EtOAc/hexane as eluent to furnish the pure product. All the products were fully characterized by their corresponding spectroscopic data (IR, 1 H and 13 C NMR and HRMS). The diastereomeric ratio was determined by 1 H NMR data of crude product and relative configurations were assigned by their coupling constants (J) values of the corresponding vicinal H- atoms (Figure 1). Electronic Supplementary Material (ESI) for RSC Advances This journal is © The Royal Society of Chemistry 2013