A mild and rapid (diacetoxyiodo)benzene-mediated formal electrophilic α-azidation of 1,3-dicarbonyl compounds using commercially available Bu4NN3 as the azide source is reported. The reaction conditions employed are based on optimization studies conducted analogous halogenations with Et4NX (X = Cl, Br, I).

An enantioselective Pd-catalyzed DAAA of α-aryl-β-oxo esters has been developed employing the (R,R)-ANDEN-phenyl Trost ligand to prepare a series α-aryl-α-allyldihydrocoumarins and 3-isochromanones. A variety aryl groups were successfully employed afford dihydrocoumarin 3-isochromanone products in high yields up 95% ee's 96%. Under these conditions, substrates containing di- mono-ortho-substituted gave highest levels enantioselectivities. This work represents first example preparation...

Abstract A modular six‐step asymmetric synthesis of two naturally occurring and three non‐natural isoflavanones containing tertiary α‐aryl carbonyls is reported. This synthetic route, utilising a Pd‐catalyzed decarboxylative protonation, produces in excellent enantioselectivities from 76–97 %. switch the sense stereoinduction was observed when different H + sources were employed, showing first example dual stereocontrol an protonation reaction. The enantioselective sativanone 3‐ o...

Abstract A highly enantioselective Pd‐catalysed decarboxylative asymmetric allylic alkylation of cyclopentanone derived α‐aryl‐β‐keto esters employing the ( R , )‐ANDEN‐phenyl Trost ligand has been developed. The product S )‐α‐allyl‐α‐arylcyclopentanones were obtained in excellent yields and enantioselectivities (up to >99.9 % ee ). This represents one most formations an all‐carbon quaternary stereogenic center reported date. reaction was demonstrated on a 4.0 mmol scale without any...

An efficient high-yielding (diacetoxyiodo)benzene-mediated alpha-halogenation of 1,3-dicarbonyl compounds utilising titanium tetrahalides as the halide source has been developed.

Electrophilic α-cyanation of activated methylene compounds was achieved under mild basic conditions using commercially available TsCN as a CN+ equivalent. A series 1,3-dicarbonyl compounds, both cyclic and acyclic, were found to be suitable substrates for this transformation. Subjecting 1,1,1-trifluoro-1,3-dicarbonyl modified procedure resulted in the formation α-cyano ketones after trifluoroacetyl group fragmentation. An efficient one-pot cyanation/pyrazole sequence 4-cyano pyrazoles from...

Treatment of 4-hydroxycoumarins and related heterocycles with TsCN under mild basic reaction conditions produces the corresponding 3-sulfinylated products in high yields. Sulfinyl transfer is proposed to occur from sulfinyl cyanate 1, generated situ by base-catalysed rearrangement TsCN.

Abstract Pd‐catalyzed decarboxylative asymmetric protonation (DAP) has been developed for sterically hindered α‐aryl lactone and dihydrocoumarin substrates. Optimization studies were conducted using δ‐lactone‐ dihydrocoumarin‐derived α‐aryl, β‐oxo‐allyl esters with 2,4,6‐trimethoxyphenyl as the aryl substituent. In absence of a chiral P,N‐ ligand, (1 R ,2 S ) ‐ (−)ephedrine, cheap readily available proton donor, induced enantioselectivities up to 92% ee 88% substrates, respectively. Bulky...

A novel and practical asymmetric synthesis of (S)-N-[[3-(3-fluoro-4-morpholinyl phenyl)-2-oxo-5-oxazolidinyl] methyl]acetamide has been developed by a new approach without recourse to chromatography it is employed for the Linezolid. This involves reaction (R)-epichlorohydrin with N-arylcarbamates subsequent regioselective epoxide ring opening resulted intermediate sodium azide. Keywords: Linezolid, antibacterial drug, synthesis, opening, one pot

Pd‐catalyzed decarboxylative asymmetric protonation (DAP) using (1 R ,2 S )‐(–)ephedrine as the proton source, previously developed for sterically hindered α‐aryl, lactone and dihydrocoumarin substrates, was applied to a range of α‐aryl β‐keto allyl ester substrates that were already successful in DAP with chiral P,N ‐ligands. An optimization study cyclopentanone‐derived β‐oxo‐allyl 2,4,6‐trimethoxyphenyl aryl substituent afforded high levels enantioselectivity (91 % ee ). This encouraged us...

Efficient oxidative α-halogenation of 1,3-dicarbonyl compounds has been achieved by employing a system comprising sub-stoichiometric amounts TiX4 (X = Cl, Br) in conjunction with environmentally benign hydrogen peroxide (H2O2) or peracetic acid (MeCO3H) as the oxidants. The end point reaction is accompanied sharp colour change.

Abstract A modular sequence to construct isoflavones with a range of methoxy‐substituted aryl substituents is presented.

Abstract Generally, the reactions with peracid give consistently cleaner products than those carried out H 2 O .

ChemInform is a weekly Abstracting Service, delivering concise information at glance that was extracted from about 100 leading journals. To access Abstract of an article which published elsewhere, please select “Full Text” option. The original trackable via the “References”

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at glance that was extracted from about 100 leading journals. To access of an article which published elsewhere, please select “Full Text” option. The original trackable via the “References”