利用一價銠金屬進行不對稱1,4-加成反應對三尖杉鹼天然物全合成之合成研究
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2020
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Abstract
本篇論文探討利用一價銠金屬及掌性雙環[2.2.1]雙烯配基L1形成之催化劑催化芳香基硼酸試劑48對環狀α,β-不飽和β-酮酯47進行不對稱1,4-加成反應。生成加成產物46為單一非鏡像異構物有產率67–99%及鏡像超越值66–99%。此加成產物46可再進行烷基化反應(C-alkylation)，建構掌性四級碳之產物45，其產物45產率43–94%及鏡像超越值66–98%。本論文探討利用此方法應用在合成天然物(−)-Cephalotaxine之可能性
This thesis studies the asymmetric 1,4-addition reaction of arylboronic acids 48 to cyclic α,β-unsaturated β-ketoester 47 catalyzed by a Rh(I)/chiral diene ligand L1 catalyst. The adducts 46 were obtained as a single diastereomer in up to 99% yield and with up to 99% ee. Furthermore, the adducts 46 underwent C-alkylaion reaction to provide products 45 with a chiral quaternary stereogenic center in up to 94% yield and with up to 98% ee. This method was used for the synthetic study toward the total synthesis of natural product (−)-Cephalotaxine.
This thesis studies the asymmetric 1,4-addition reaction of arylboronic acids 48 to cyclic α,β-unsaturated β-ketoester 47 catalyzed by a Rh(I)/chiral diene ligand L1 catalyst. The adducts 46 were obtained as a single diastereomer in up to 99% yield and with up to 99% ee. Furthermore, the adducts 46 underwent C-alkylaion reaction to provide products 45 with a chiral quaternary stereogenic center in up to 94% yield and with up to 98% ee. This method was used for the synthetic study toward the total synthesis of natural product (−)-Cephalotaxine.
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一價銠金屬, 掌性雙環[2.2.1]雙烯配基, 環狀α,β-不飽和β-酮酯, 不對稱1,4-加成反應, 天然物, Rh(I)/chiral diene ligand catalyst, asymmetric 1,4-addition reaction, α,β-unsaturated β-ketoester, natural product