一價銠金屬催化氮-甲氧羰基之1,2-二氫吡啶進行不對稱氫芳基化反應
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2021
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本篇論文探討使用一價銠金屬及掌性雙環[2.2.1]雙烯配基L3c及L11a所形成之催化劑，使用環戊基甲基醚為溶劑，甲醇為質子添加劑，反應使用1,2-二氫吡啶14及四芳基硼鈉15為起始物於80 ℃反應24小時進行不對稱加成反應，生成一系列3號位具有芳基取代的掌性1,2,3,4-四氫吡啶產物16及少量四號位加成產物59之混合物，混合產率18–88%，可單獨鑑定主產物16之鏡像超越值為60–96%。另外，利用掌性1,2,3,4-四氫吡啶化合物(R)-16af及(R)-16bf經雙鍵還原及去保護反應成功得到(+)-Preclamol [(+)-4] 前驅物17，兩步總產率為兩步總產率為27%及46%。
This thesis describes an enantioselective 1,2-addition of sodium tetraarylborates 15 to 1,2-dihydropyridine 14 in cyclopentyl methyl ether at 80 ℃ with 5.0 equiv of methanol as an additive in the presence of 3.0 mol % of Rh(I)-catalyst in situ generated from the [RhCl(C2H4)2]2 and chiral bicyclo[2.2.1]heptadiene ligand L3c and L11a. The desired 3-aryl-tetrahydropyridines 16 and a small amount of addition product 59 were generated in 18–88% mixed yields and the ee value of chiral compound 16 is determined independently as 60–96%. In addition, the formal synthesis of (+)-Preclamol precursor 17 was achieved by reduction and deprotection of compound (R)-16af and (R)-16bf in 27% and 46% yield for 2 steps.
This thesis describes an enantioselective 1,2-addition of sodium tetraarylborates 15 to 1,2-dihydropyridine 14 in cyclopentyl methyl ether at 80 ℃ with 5.0 equiv of methanol as an additive in the presence of 3.0 mol % of Rh(I)-catalyst in situ generated from the [RhCl(C2H4)2]2 and chiral bicyclo[2.2.1]heptadiene ligand L3c and L11a. The desired 3-aryl-tetrahydropyridines 16 and a small amount of addition product 59 were generated in 18–88% mixed yields and the ee value of chiral compound 16 is determined independently as 60–96%. In addition, the formal synthesis of (+)-Preclamol precursor 17 was achieved by reduction and deprotection of compound (R)-16af and (R)-16bf in 27% and 46% yield for 2 steps.
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鏡像選擇性, 一價銠金屬催化, 氫芳基化反應, 1, 2‐二氫吡啶, 四芳基硼鈉試劑, 不對稱加成反應, 掌性, 掌性雙環[2.2.1]雙烯配基, enantioselective, Rhodium(I)-catalyzed, hydroarylation, 1, 2- dihydropyridines, sodium tetraarylborates, asymmetric addition, chiral, chiral bicyclo[2.2.1]diene ligands