以掌性銠金屬雙烯錯合物催化不對稱1,4-加成反應合成掌性含氮分子

Abstract

壹、銠催化芳基硼酸與氮-特丁氧羰基保護的α,β-不飽和γ-內醯胺的不對稱1,4-加成反應： 我們運用由左旋醋酸冰片酯合成出的一系列掌性雙環[2.2.1]二烯配體L1與一價銠金屬形成之催化劑，催化各種芳基硼酸14與氮-特丁氧羰基保護的α,β-不飽和γ-內醯胺195a進行不對稱1,4-加成反應。在0.5 mol%的Rh(I)/L1f催化劑量下，本反應可生成高產率 （31–>99%） 及高鏡像選擇性（93–>99.5% ee）的加成產物(R)-197。此法可應用至苯基海人酸207以及MCHR1拮抗劑302的形式合成。

貳、銠催化芳基硼酸與α-取代的β-硝基丙烯酸酯的不對稱1,4-加成反應： 本部分內容綜述各種芳基硼酸14與α-取代的β-硝基丙烯酸酯361的不對稱共軛加成反應。以5.0 mol%的Rh(I)/L1e進行催化反應，並利用KHF2做為添加劑，可製備出加成產物(R)-362，產率最高可至63%，鏡像超越值高達99% ee。此方法可應用至具有光學活性的β2,2-胺基酸369，β-內醯胺375，以及α,β2,2,α-胜肽380的不對稱合成。

I.Rhodium-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to N-Boc Protected α,β-Unsaturated γ-Lactam: A family of chiral bicyclo[2.2.1]heptadiene ligands L1 synthesized from L-(−)-bornyl acetate were utilized in the Rh(I)-catalyzed enantio- selective 1,4-addition of various arylboronic acids 14 to N-Boc-protected α,β-unsaturated γ-lactam 195a. In the presence of 0.5 mol% of a Rh(I)/L1f catalyst, the corresponding adducts (R)-197 were isolated in high yields (31–>99%) and excellent enantioselectivities (93–>99.5% ee). This metho- dology was employed for the formal synthesis of phenylkainic acid 207 and MCHR1 antagonist 302.

II.Rhodium-Catalyzed Asymmetric 1,4-Addition of Arylboronic Acids to α-Substituted β-Nitroacrylates: Asymmetric conjugate addition of various arylboronic acids 14 to α-substituted β-nitroacrylates 361 was described. The reaction, catalyzed by 5.0 mol% of Rh(I)/L1e, provided the conjugate adduct (R)-362 in up to 63% yield and up to 99% ee using KHF2 as an additive. This method are applied to the asymmetric synthesis of optically active β2,2-amino acid 369, β-lactam 375, and α,β2,2,α-peptide 380.