臺灣博碩士論文加值系統

本 論 文 提 出 之 研 究 計 畫 , 以 8-aryl-8-
azaheptafulvenes 為主反應物 , 來進行分子間 [piMs+piNs]環化加
成反應 , 進 而 瞭解影響鍵結合過渡狀態 ( BondingTranstion
State ) 之立體障蔽效應 ( Steric Effect ) 和二次軌 域 作 用吸引力
( Stabilizing Secondary Orbital Interaction ) 相互間之
競爭性 , 以及對加成反應中之立體選 擇 性 (
Diastereoselectivity ) , 位 置 選 擇 性( Periselectivity )
和位向選擇性 ( Regioselectivity ) 的競爭性反應機構之研究 .
一 系 列 之 8-Aryl-8-azaheptafulvenes 和
6,6-Dimethylfulvene , 6-(p-Nitrobenzoxy)fulvene , 在 Benzene迴
流以及 Xylene 迴流 , 均得 Anti-[6+4] 環化加成生成物 2-2(E)
, 2-2(Z) , 2-4(E) , 2-4(Z) ~ 2-11(Z)' , 顯示出極佳的位置選擇性
, 位向選擇性和立體選擇性 . Fulvenes環外取代基以 t-Butyl
group 取代時 , 因立體障蔽效應故未能夠進行任何分子間 [piMs+
piNs] 環化加成反應 .

In order to determine the product selectivity , such
as the diastereoselectivity , periselectivity and
regioselectivity ,which is governed by steric effect or by
stabilizing secondaryorbital interactions of the exocyclic
substituents on the 8-aryl-8-azaheptafulvenes , the
intermolecular cycloadditionsof asymmetrically
substituted and symmetrically di-substituted fulvenes
with 8-aryl-8-azaheptafulvenes areinvestigated . The
intermolecular cycloaddition reactions of 8-aryl-8-
azaheptafulvenes with 6,6-dimethylfulvene in
refluxingbenzene , give only Anti-[6+4] ( E forms anrd
Z forms ) cycloadducts 2-2(E) , 2-2(Z) , 2-4(E) , 2-4(Z) ~
2-11(Z)' .When the reaction was carried out in
refluxing xylene ,Anti-[6+4] ( E forms and Z forms )
cycloadducts werealso observed . No cycloaddition
reaction was observedwhen the balky exocyclic
substituted 6-t-butyl-6-methylfulvene ( 5 , page 95 )
was reacted with 8-aryl-8-azaheptafulvenes .