A Theoretical Study On Reactivity Of Alder-ene Reaction;The Synthesis Of Series Of Sterically Hindered Phosphine Ligand

This paper includes two parts: a theoretical study on reactivity of Alder-ene reaction and the synthesis of series of sterically hindered phosphine ligand.In chapter one, the theoretical study on reactivity of Alder-ene reaction was investigated. The Alder-ene reaction is a classic synthesis method, which was first reported by Alder in 1943. It mainly occurs between an alkene and an allylic hydrogen, which is an efficient method to build C-C bonds. The Alder-ene reaction is widely used in building new organic compounds and natural products and it is also important in the asymmetric synthesis. In this part, we choose hetero-substituted propylene(propylene, ethylidenesilane, ethanimine, ethylidenephosphine, acetaldehyde, ethanethial) and propylene as main substance. Density functional theory(DFT) methods CBS-QB3, G3B3, M11, B3-LYP are employed to investigate the reactivity of hetero-substituted propylene in uncatalyzed Alder-ene type reactions. Computational results suggest that the reactivity trend for third-period element substituted ene reactants is higher than that of the corresponding second-period element substituted ene reactants. Theoretical calculations also indicate that for the same period element substituted ene reactants, the reactivity trend is ethylidenesilane > ethylidenephosphine > ethanethial, and propylene > ethanimine > acetaldehyde. However, the distortion-interaction analysis only at the transition states, which reveals that the activation barrier mainly derives from the interaction energy since the change of interaction energy is much bigger than that of the change of distortion energy, is limited to explain the reactivity difference. The distortion-interaction analysis along the reaction pathway is employed to elucidate the reactivity difference origin. Our theoretical calculation indicates that the reactivity of hetero-substituted Alder-ene reaction is controlled by the relative interaction energy. The lower relative interaction energy leads to an earlier transition state, which also has a lower distortion energy and can be attributed to orbital interaction, closed-shell repulsion, and static repulsion.In chapter two, the synthesis of a series of sterically hindered phosphine ligands was investigated. Phosphine ligands are commonly used as transient ligands, which have greater usage value. What's more, sterically hindered phosphine ligand can respond to many special catalytic effect due to its special space structure. In this paper, we introduced the synthesis of 9-phosphatriptycenesuses from inexpensive and commercially available 1-bromo-3-methoxybenzene as starting materials. And target product were characterized through nuclear magnetic resonance spectra.