Computational Structure Reassignment of Laurefurenynes A and B

2013-09-09T16:22:14Z (GMT) by Robert Paton
<p>The originally assigned stereostructures of laurefurenynes A and B have been reassigned on the basis of DFT calculations of NMR chemical shifts. The deposited files are outputs from geometry optimizations and subsequent calculations of shielding tensors in CPCM, for each of the putative diastereomers. The correct structure is number 6, as described in the paper ( </p> <p> </p> <p>The data was generated as follows:</p> <p>For each distereomer a 10,000 step Monte Carlo Multiple Minimum (MCMM) conformational search was performed using the MMFF force field. Resulting molecular mechanics geometries within 10 kJ/mol of the global energy minimum were reoptimized with Gaussian09 at the wB97XD/6-31G(d) level with CPCM chloroform. Following these DFT optimizations duplicate conformers were removed to give 2733 conformations across all diastereomers (present as Gaussian formatted output files). For each DFT optimized conformer, shielding tensors were computed at the GIAO-mPW1PW91/6-311G(d,p) level of theory with CPCM chloroform solvation (present as Gaussian formatted output files). The conformational ensemble average 13C and 1H shielding tensor was computed from Boltzmann factors at 298K using the electronic energies (present as text files).</p> <p> </p>