| Abstract: | 以雙喃稠倍半桶烯41探討分子內平行雙烯的親電性加成反應。將化合 物41和溴在低溫反應，得化合物55,56;和氯化硒苯反應,得化合物63,64和 溴化硒反應,得化合物65,66;若與溴化氫反應,可得化合物62,這些加成產 物55,56,63,64,66,62皆經由跨環碳-碳鍵形成屬於"N-tyope"結構之反應 模式。而化合物41和N-溴丁二醯亞胺,水反應,可得"U-type"中間物的衍生 化合物69及重排過的化合物70.將化和物41與間-氯過苯甲酸反應,除加成 之環氧醚外,亦得到經分子內氫負離子的轉移而形成之化合物85. 親電 性化合物與平行雙烯橋反應之加成反應為向選擇性為endo或exo,可由氫- 碳核磁共振光譜鑑定,或由X-ray繞射晶體的結果說明,亦可以化學方法間 接證明.例如:化合物55,56,62進行去溴反應得化合物57, 從產物57之分子 對稱型式及光譜判定其跨環碳-碳鍵形成為"N-type"結構. 將化合物41 進行氫硼烷化-氧化反應可得醇89,在經氧化酪氧化成酮90,化合物90和三 甲基矽三氟化磺酸反應得三甲基矽化乙烯醚91,化合物91之照光反應可得 分子間環化產物92及醇93,化合物92,93為籠狀化合物,可進行熱烈解的反 應,探討合成碗狀系列多環烴。
Bis (tetrahydrofurano) sesquibarrelene 41 has been prepared to study the electrophilic addition reactions on the paralle C=C double bonds of 41 . Bromination of 41 at low temperature produced compound 55 and 56 via transannular C=C formation ; similarly, reaction with phenylselenenyl chloride gane compounds 63 and 64; reaction with phenylselenenyl bromide gave compounds 65 and 66. Reaction with hydrogen bromide generated from tetrahydronaphthalene and bromine gave 62. Products analysis indicated that transannular C=C formation formed in cross manner was the major pathway. Reaction of compound 41 with N- brinisyccinimide and water afforded ether 69 via a "U-type" intermediate and intramolecular substitution accompany with tearrangement product 70. Epoxidation of compound 41 led to epoxide 84 and the rearrangement product 85. The structure of thes adducts have been determined by spectroscopic (NMZR and X-ray diffraction) and chemical means. The formation of rearrangement product has been rationalized by teaction mechanisms. Hydroboration -oxidation of compound 41 followed by oxidation, silylation and photocyclization gave 92 and 93. Thermal reaction of alcohol 93 did not give the desired [2+2] retrocyclization. |
