第一章 此章展示了利用NaBARF催化2-酯基環戊二烯與亞硝基苯進行[2+2]-環化加成反應,得到兩個能夠分離之位置異構物的6-氧-7-雜氮二[3.2.0]庚環產物,且於熱平衡下重排為相同產物。由於此反應為可逆之[2+2]-亞硝基/烯環化加成反應,在熱反應平衡下,會具有選擇性的進一步生成4-胺基環戊烯-3-酮產物;在C(4)位置沒有取代基的情況下,受質則會在與亞硝基苯加成後,快速地進行擴環,有效率的得到一六環之哌啶酮產物。 第二章 此章節介紹了我們成功利用金金屬催化劑催化α-苯基重氮酮與三取代之烯類化合物進行[3+2]-環化反應,得到具有呋喃(furan)結構之產物。反應過程中,α-苯基重氮酮會形成α-氧代金碳烯中間體,此時烯類化合物能夠作為親核體攻打金碳烯中間體,形成一陽離子丙烯基中間體,最後環化得到有用的呋喃(furan)結構之產物。
Chapter I NaBARF catalyzes the [2+2]-cycloaddition of 1,4-disubstituted cyclopenta-1,3-dien-2-yl esters with nitrsobenzene in toluene, affording two isolable regioisomers of 6-oxa-7-azabicyclo[3.2.0]heptanes, which thermally rearranged into the same 4-aminocyclopent-1-en-3-ones chemoselectively. The chemoselectivity of this reaction is due to a rapidly reversible nature of the initial [2+2]-nitroso/alkene cycloadditions. In the case of 4-substituted cyclopenta-1,3-dien-2-yl esters, their initial [2+2]-cycloaddition intermediates undergo a rapid ring expansion to afford six-membered piperidone derivatives efficiently. Chapter II Gold(I)-catalyzed [3+2]-annulations of α-aryl diazoketones with trisubstituted alkenes of substituted-1,3-butandienes affording the furan derivatives. In the mechanism, α-aryl diazoketones will turn into α-oxo gold carbenes. Afterwards, diene compounds as nucleophile attacks the gold carbene intermediates forming a allyl cation intermediates. Finally, the reaction proceeds cyclization and delivers the useful furan structure.