Successively Recycle Waste as Catalyst: A One-Pot Wittig/1,4-Reduction/Paal–Knorr Sequence for Modular Synthesis of Substituted Furans
摘要:
A one-pot tandem Wittig/conjugate reduction/PaalKnorr reaction is reported for the synthesis of di- or trisubstituted furans. This novel sequence first demonstrates the possibility of successively recycling waste from upstream steps to catalyze downstream reactions.
Polymer-Stabilized Palladium Nanoparticles for the Chemoselective Transfer Hydrogenation of α,β-Unsaturated Carbonyls: Single-Step Bottom-Up Approach
作者:Sanjit K. Mahato、Rafique Ul Islam、Chiranjit Acharya、Michael J. Witcomb、Kaushik Mallick
DOI:10.1002/cctc.201300985
日期:2014.3.19
Polypyrrole stabilised palladium nanoparticles show good catalytic efficiency for the chemoselective transfer hydrogenation of α,β‐unsaturated carbonyl compounds. The catalyst is very specific and selectively hydrogenates the olefins or acetylenes only, without affecting the carbonyl moiety, with an excellent yield of products for a wide range of substrates.
C7‐Functionalization of Indoles via Organocatalytic Enantioselective Friedel‐Crafts Alkylation of 4‐Amino‐ indoles with 2‐Butene‐1,4‐diones and 3‐Aroylacrylates
作者:Tongkun Huang、Yunlong Zhao、Shanshui Meng、Albert S. C. Chan、Junling Zhao
DOI:10.1002/adsc.201900377
日期:2019.8.5
An efficient protocol for the enantioselective C7 Friedel‐Crafts alkylation between 4‐aminoindoles and 2‐butene‐1,4‐diones or 3‐aroylacrylates was reported. This process was catalyzed by a chiral phosphoric acid, affording the corresponding 1,4‐disubstituted indoles in moderate to high yields with good to high enantioselectivities. This reaction could be performed on a gram scale without loss of efficiency
used as an aza-Michael donor in organocatalyticasymmetricreactions with symmetric and nonsymmetric unsaturated 1,4-diketones. After hydrolysis (in situ), the N-substituted isatins were obtained in high yields (up to >95%) with high enantioselectivity (up to 95%). Isatin was activated by derivatization to a Schiff base with aniline and used as an aza-Michael donor in organocatalyticasymmetric reactions
sulfinamide bisphosphine catalysts (Wei‐Phos) were developed. These could be easily prepared from commercially available starting materials. Wei‐Phos has shown good performance in the very challenging intermolecular cross‐Rauhut–Currier reactions of vinyl ketones and 3‐acyl acrylates or 2‐ene‐1,4‐diones, leading to the R‐C products in high yields with up to 99 % ee under 2.5–5 mol% catalyst loading. The highly