利用膦試劑誘導生成季鏻鹽以合成雙雜環化合物及呋喃[3,2-c]香豆素衍生物

Abstract

第一章：利用吲哚、水楊醛及醯氯行縮合/醯化/Wittig連鎖反應，在酸以及膦試劑的誘導下可以成功地合成吲哚-苯并呋喃加成物。此反應所需條件十分溫和，不需使用過渡金屬催化，起始物也不需預先處理或活化，為一合成雙雜環化合物的新路徑。反應中所生成的中間體為可簡單分離並純化的穩定季鏻鹽，是一具有潛力的Wittig試劑。

第二章：利用查耳酮香豆素作為起始物，與膦試劑及醯氯反應後可有效率地得到應用性多元的季鏻鹽中間體，其可加入飽和碳酸氫鈉水溶液切除膦試劑，得到呋喃[3,2-c]香豆素產物；亦可加入鹼及高活性的羰基化合物並進行分子間Wittig反應，得到具有烯烴的呋喃[3,2-c]香豆素產物。此法的反應條件十分溫和，可在短時間內得到預期產物。Chapter I: An acid-mediated condensation/acylation/Wittig tandem reaction between indoles, salicylaldehyde dericatives and acyl chlorides to generate indole-benzo[b]furan adducts is described. This highly efficient approach towards such bis-heterocyclic compounds via easily accessible phosphonium salt intermediates has not been reported. Under metal-free reaction conditions and without preactivation of the coupling partners, this synthetic strategy provides the desired products in moderate to good yields in a two-step procedure. Furthermore, we also developed a protocol in a one-pot approach with the only slightly diminished yield of the desired adduct.

Chapter II: A Bu3P-mediated cyclisation reaction of 3-cinnamoyl-4-hydroxy-2H-chromen-2-ones via electrophilic addition of acyl chlorides towards the synthesis of highly functionalized furo[3,2-c]coumarins bearing a phosphorus ylide moiety is described. These unprecedented cyclisation reactions proceed under mild reaction conditions within short reaction times (1 min to 1 h), and can be further applied in the synthesis of alkenyl-substituted furo[3,2-c]coumarins after the treatment with carbonyl electrophiles under basic condition.