Theoretical studies on the Mo-catalyzed asymmetric intramolecular Pauson-Khand-type [2 + 2 + 1] cycloadditions of 3-allyloxy-1-propynylphosphonates

摘要

Density functional theory (DFT) was used to investigate the Mo-catalyzed intramolecular Pauson-Khand reaction of 3-allyloxy-1-propynylphosphonates. All intermediates and transition states were optimized completely at the B3LYP/6-31 G(d,p) level [LANL2DZ(f) for Mo]. In the Mo-catalyzed intramolecular Pauson-Khand reaction, the C–C oxidative cyclization reaction was the chirality-determining step, and the reductive elimination reaction was the rate-determining step. The carbonyl insertion reaction into the Mo–C(sp 3) bond was easier than into the Mo–C = C bond. And the dominant product predicted theoretically was of (S)-chirality, which agreed with experimental data. This reaction was solvent dependent, and toluene was the best among the three solvents toluene, CH3CN, and THF.