一價銠金屬催化氮-苄基之3-硝基吡啶胺鹽進行不對稱芳基化反應

Abstract

本篇論文探討使用一價銠金屬與掌性雙環[2.2.1]雙烯配基L1所形成的催化劑，反應溶劑使用甲醇，反應溫度為70 ℃，催化3-硝基吡啶胺鹽(3-nitropyridinium salts，1)與四芳基硼鈉2進行不對稱1,2加成反應，生成一系列2號位具有芳基取代的掌性1,2-二氫吡啶3。共有21的例子，產率17–87%，鏡像超越值為50–98%。值得注意的是:將吡啶胺鹽的3號位取代基更換成酯基、氰基皆有不錯的成果，共有4個例子，產率59–80%，鏡像超越值為74–98%。此舉也提升了未來應用的可能性。另外，使用2號位具有苯基取代的掌性1,2-二氫吡啶3aa，進行硝基還原反應、還原胺化反應及氫化反應，可以順利合成組織胺H1受體拮抗劑的藥物10

This thesis describes an enantioselective rhodium-catalyzed 1,2-arylation of 3- nitropyridinium salt 1. 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 L1a, the asymmetric reaction of sodium tetraarylborates 2 and 3-nitropyridinium salts 1 gives a series of chiral 2- aryl-5-nitro-1,2-dihydropyridine derivatives 3 in 17–87% yields and 74–98% ees. N-nicotinate salts and 3-cyanopyridinium salts are compatible as starting materials in this protocol. In addition, the synthesis of the bioactive piperidines 10 is achieved via the reduction of the dihydropyridine 3aa, the reductive amination, and hydrogenation.