銠金屬(I)結合掌性雙環[2.2.1]雙烯配體催化四芳香基硼鈉鹽對β,β-雙取代 α,β-不飽和酮類化合物進行不對稱1,4-加成反應

Abstract

本文利用過渡金屬銠(I)金屬和掌性雙烯配基 (L2B) 當作催化劑，催化四芳香基硼鈉鹽48，在2-甲基四氫呋喃溶劑中，以甲醇當作添加劑，於80 °C環境下，對β,β-雙取代α,β-不飽和環狀酮類化合物進行不對稱1,4-加成反應，建構一系列具有掌性的四級碳中心的化合物。以3或是1 mol%的銠金屬催化可以得到3到83%的產率，87到>99.5%鏡像超越值的加成產物49。 接著，將具有高產率及高選擇性之產物49a當作起始物，進一步應用於合成出具掌性之內醯胺(55a、55b)及內酯(56a、56b)化合物。In this thesis, a practical synthesis of optically active ketones 49 bearing a β-quaternary chiral center from asymmertric conjugated reaction of sodium tetraarylborates 48 to β,β-disubstituted α,β-unsaturated ketones is described. In the presence of 1mol% or 3mol% of rhodium catalyst in situ generated from the reaction of [RhCl(C2H4)2]2 and chiral diene ligand L2B, the asymmetric conjugate addition reaction, conducted at 80 °C in 2-methyltetrahydrofuran using MeOH as an additive, of a variety of sodium tetraarylborates 48 toβ,β-disubstituted α,β-unsaturated ketones furnished adducts 49 in up to 83% yield and up to >99.5% ee. For the synthetic application, enantio-enriched compound 49a was transformed into chiral lactams (55a and 55b) and lactones (56a and 56b) respectively via Schmidt reaction and Baeyer Villiger oxidation reaction.