An iridium/f-amphol catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti products were obtained in high yields (up to 98%) with good diastereoselectivity (up to 96:4 diastereometic ratio (dr)) and excellent enantioselectivity (up to >99% enantiomeric excess (ee)). A catalytic model is proposed to explain the
The first catalyticasymmetric chlorination of isoxazolinones is reported. A planar chiral ferrocene based palladacycle managed to catalyze this reaction type with high enantioselectivity providing high to excellent yields. The chlorination products are useful substrates for SN2 type reactions as is demonstrated with NaN3. This was key for the synthesis of an α-azido β-aminoacid derivative.
报道了异恶唑啉酮的第一次催化不对称氯化。基于平面手性二茂铁的钯环设法以高对映选择性催化这种反应类型,提供高至优异的产率。如NaN 3所示,氯化产物是S N 2 型反应的有用底物。这是合成 α-叠氮基 β-氨基酸衍生物的关键。
Carbocation Lewis Acid TrBF<sub>4</sub>-Catalyzed 1,2-Hydride Migration: Approaches to (<i>Z</i>)-α,β-Unsaturated Esters and α-Branched β-Ketocarbonyls
作者:Wansong Shang、Depeng Duan、Yongjun Liu、Jian Lv
DOI:10.1021/acs.orglett.9b03005
日期:2019.10.4
CarbocationLewisacid TrBF4-catalyzed 1,2-hydride migration of α-alkyldiazoacetates themselves or in situ-generated cross-coupling adducts of aldehydes and α-alkyldiazoacetates has been developed, affording (Z)-α,β-unsaturated esters and α-branched β-ketocarbonyls, respectively, in good yields and with high regioselectivities.