Denmark and Baiazitov S1 Intramolecular [4+2] Cycloaddition of Nitroalkenes for Construction of Vicinal Quaternary Stereocenters Scott E. Denmark* and Ramil Y. Baiazitov Roger Adams Laboratory, Department of Chemistry, University of Illinois, 600 South Mathews Avenue, Urbana, Illinois 61801 SUPPORTING INFORMATION Table of Contents Page General Experimental S1 Literature Preparations S3 Synthesis Scheme S3 Experimental Procedures and Configurational Assignments S4 References S21 General Experimental 1 H and 13 C NMR spectra were recorded on Varian Unity-400 (400 MHz 1 H, 101 MHz 13 C), Unity-500 (500 MHz 1 H, 126 MHz 13 C) and Varian Unity Inova 500 (500 MHz 1 H) spectrometers in deuterochloroform. Spectra were referenced to residual chloroform (7.26 ppm, 1 H; 77.0 ppm, 13 C). Data are reported in the following order: chemical shift in ppm (δ); multiplicities are indicated (br (broadened), s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet)); coupling constants, J, are reported in hertz (Hz); integration is provided; and assignment is indicated. 1 H and 13 C NMR assignments are corroborated by 2D experiments (COSY, HMQC, and HMBC). Spectra are available on request from denmark@scs.uiuc.edu. Mass spectrometry was performed by the University of Illinois Mass Spectrometry Center. Electron impact (EI) spectra were performed on a Micromass 70-VSE spectrometer, chemical ionization (CI) spectra were obtained on a Micromass 70-VSE spectrometer using methane as the carrier gas, electrospray ionization (ESI) spectra were obtained from Micromass Q-TOF spectrometer. Data are reported in the form of m/z (intensity relative to base peak = 100). Infrared spectra (IR) were recorded on a Mattson Galaxy 5020 spectrophotometer. Peaks are reported in cm -1 with indicated intensities: s (strong, 67 – 100% absorption), m (medium, 34 –