由多官能性的磷兩性離子經由分子內選擇性的 Wittig 反應合成多取代苯并呋喃和呋喃[3,2-c]香豆素
Abstract
本論文分為兩大主題，探討由多官能性的磷兩性離子經由分子內選擇性的 Wittig 反應合成多取代苯并呋喃和呋喃[3,2-c]香豆素以及有機不對稱催化合成多取代的苯并吡喃[3,4-c]吡咯啶衍生物。
第一部分：本實驗室衍生化自行開發的磷兩性離子化合物，並有效的控制此兩性離子行 Wittig 反應的選擇性，且穩定的捕抓其反應過程中所生成的中間體，再利用此中間體性質趨向的不同，合成苯并呋喃或是呋喃[3,2-c]香豆素衍生物，此選擇性的控制在化學領域上相當的新穎，且皆可得到相當良好的結果。
第二部分：利用香豆素衍生物以及亞胺衍生物，經由 [3+2] 反應，合成出具有高產率、高非鏡像異構物比以及高鏡像超越值的吡喃[3,4-c]吡咯啶衍生物，並且在其衍生化合成中具有相當高的價值值得進一步的討論。
The thesis is divided into two parts： In the first part, chemoselective synthesis of substituted benzofurans and furo[3,2-c]coumarins from functional phosphorus zwitterions via intramolecular Wittig reactions is described. Based on our previous studies, a phosphine-triggered intramolecular Wittig reaction with high efficiency via phosphorus zwitterions as key intermediates has been developed. The studies included chemoselectivities of acylations and intramolecular Wittig reactions. By employing different addition sequence of the acyl chloride and phosphine reagent, the corresponding furo[3,2-c]coumarin derivative can be synthesized chemoselectively, which has not be reported, to the best of our knowledge. In the second part, enantioselective synthesis of pyran[4,3-b]chromene derivatives via organocatalyzed [3+2] cycloaddition has been investigated. Cinchona alkaloid derived organocatalysts as bases have been exclusively examined for asymmetric [3+2] cycloaddition of o-hydroxy aromatic aldimine and coumarins. In addition, the desired products can be further transformed into complex tricyclic products.
The thesis is divided into two parts： In the first part, chemoselective synthesis of substituted benzofurans and furo[3,2-c]coumarins from functional phosphorus zwitterions via intramolecular Wittig reactions is described. Based on our previous studies, a phosphine-triggered intramolecular Wittig reaction with high efficiency via phosphorus zwitterions as key intermediates has been developed. The studies included chemoselectivities of acylations and intramolecular Wittig reactions. By employing different addition sequence of the acyl chloride and phosphine reagent, the corresponding furo[3,2-c]coumarin derivative can be synthesized chemoselectively, which has not be reported, to the best of our knowledge. In the second part, enantioselective synthesis of pyran[4,3-b]chromene derivatives via organocatalyzed [3+2] cycloaddition has been investigated. Cinchona alkaloid derived organocatalysts as bases have been exclusively examined for asymmetric [3+2] cycloaddition of o-hydroxy aromatic aldimine and coumarins. In addition, the desired products can be further transformed into complex tricyclic products.
Description
Keywords
苯并呋喃, 呋喃香豆素, 兩性離子, 選擇性化學, Benzofuran, Furocoumarin, Zwitterion, Chemoselectivity