The Study Of 1,2-dihydropyridine Derivatives Involved Diels-Alder Reaction

Diels-Alder reaction is a very typical electrophilic cyclization reaction, which can simultaneously form two carbon-carbon bonds and generate at most four chiral centers. It has an excellent atom economy. At present, Diels-Alder reaction has become one of the most important synthetic methods for six-membered cyclic compounds, natural terpenoids and piperidine derivatives. In this thesis, we have studied 1,2-dihydropyridine involved Diels-Alder reaction and synthesized versatile heterocyclic spirooxindoles:1. We have found that the functionalized 1,2-dihydro-2-oxospiro[3H-indole-3,2’-[2H,9aH-pyrido[2,1-b][1,3]oxazines]], which were obtained from three-component reaction of pyridines, methyl acetylenedicarboxylate or propiolate and N-alkylisatins, display to be efficient dienes for Diels-Alder reactions. The Diels-Alder reaction of functionalized 1,2-dihydropyridines with (E)-3-phenacylidene-2-indolinones provides facile access to the complex dispirooxindoline fused [1,3]oxazines in high yields and with good diastereoselectivity. All products were characterized by IR, NMR and HRMS spectroscopy. The single crystal structures of ten products in this part were measured by X-ray diffraction method, which help to determine the configuration of the synthetic compounds.2. We investigated the three-component reactions of 4-cyanopyridine (ethyl isonicotinate), methyl propiolate (dimethyl acetylenedicarboxylate) and N-alkylisatins, and successfully found very interesting Diels-Alder cyclodimerization between the in situ generated spiro[3H-indole-3,2’-[2H,9aH-pyrido[2,1-b][1,3]oxazines]]. This three-component reaction provided a facile access to complex polycyclic dispirooxindole derivatives in good yields and with high diastereoselectivity. The obtained spiro compounds were fully characterized by IR, NMR and HRMS spectroscopy. The single crystal structures of five products were measured by X-ray diffraction method.3. We successfully developed an efficient protocol for the synthesis of the functionalized triphenylphosphanylidene spiro[cyclopent[2]ene-1,3’-Indolines] from three-component reaction of triphenylphosphine, acetylenedicarboxylates and 3-phenacylideneoxindole. The advantages of the reactions are using readily available starting materials, mild reaction conditions, operation simplicity and high yields. The compounds of this reaction were all characterized by IR, NMR and HRMS spectroscopy. Furthermore, the single crystal structures of three products were measured by X-ray diffraction method.