Acid-Catalyzed Synthesis of α,β-Disubstituted Conjugated Enones by a Meyer-Schuster-Type Rearrangement in Allenols
作者:Benito Alcaide、Pedro Almendros、Sara Cembellín、Teresa Martínez del Campo
DOI:10.1002/adsc.201400928
日期:2015.3.23
A novel, direct and simple methodology to gain access to α,β‐disubstituted conjugated enones from α‐allenols in a sustainable metal catalysis context, considering the inexpensiveness and environmentally friendliness of iron(III) species and protons, has been developed.
H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub>/SiO<sub>2</sub>: An Eco-Friendly Alternative for the Stereo-, Regio- and Chemoselective Claisen-Schmidt Condensation
作者:Bibi Fatemeh Mirjalili、Zahra Zaghaghi
DOI:10.1002/jccs.200800104
日期:2008.6
H 3 PW 12 O 40 /SiO 2 or (PW/SiO 2 ) promotes the regio-, stereo- and chemoselectiveClaisen-Schmidtcondensation with improved yields.
H 3 PW 12 O 40 /SiO 2 或 (PW/SiO 2 ) 促进了区域选择性、立体选择性和化学选择性的 Claisen-Schmidt 缩合,并提高了产率。
Zr(HSO<sub>4</sub>)<sub>4</sub>/SiO<sub>2</sub> as an Efficient Alternative Catalyst for the Claisen-Schmidt Condensation
作者:Bi Bi Fatemeh Mirjalilia、Abddhamid Bamoniri、Masoumeh Alipour、Mohammad Ali Karimi Zarchia
DOI:10.1515/znb-2008-1213
日期:2008.12.1
Zr(HSO4)4/SiO2 promotes the regio-, stereo- and chemoselectiveClaisen-Schmidtcondensation of aromatic aldehydes with ketones under solvent-free conditions with improved yields. The work-up of the reaction mixture is simple, and the catalyst is easily removed from the products by simple filtration.
stereochemistry of the asymmetric conjugate addition of alkyl thiols to α-substituted α,β-unsaturatedketones, a class of carbonyls that has never before succumbed to a catalytic approach. The judicious choice of acidic additives and reaction media switches the sense of the catalyst's diastereoselection, thereby affording either the syn or anti product with high enantioselectivity.
Primary allylic amines with enantiomeric excesses from 97 to >99% were prepared by asymmetric transfer hydrogenation of α,β-unsaturated N-(tert-butylsulfinyl)ketimines followed by removal of the sulfinyl group. The effect caused by different substituents at the C═C bond and at the iminic carbon atom on the chemoselectivity of the reduction was studied. The desired enantiomer of the final allylic amine