Photoredox catalysed allylic trifluoromethylation via ring opening of vinyl cyclopropanes using Langlois reagent

Trifluoromethylation of vinylcyclopropanes (VCPs) has been developed under mild reaction conditions to synthesize allylic trifluoromethylated derivatives with high yield and E/Z selectivity using visible light photo-redox catalysis and Langlois reagent (CF₃SO₂Na) as a trifluoromethylation source. Further, we demonstrate a gram scale synthesis procedure for a trifluoromethylation of vinylcyclopropane.     

A simple one-pot entry to cyclic ethers of varied ring sizes from diols via phosphonium ion induced iodination and base catalyzed Williamson etherification

A novel and an efficient one-pot cyclization method using triphenylphosphine, iodine and a nitrogenous base has been established for the synthesis of cyclic ethers of various ring sizes. This appears to follow a two-step procedure, which includes preferential substitution of one hydroxyl group by an iodide generated in situ followed by an intramolecular ring closure through the attack of a free hydroxyl group or the more nucleophilic oxide ion.     

A one-pot access to 6-substituted phenanthridines from fluoroarenes and nitriles via 1,2-arynes

[reaction: see text] A one-pot, t-BuLi-induced synthesis of 6-substituted phenanthridines from fluoroarenes and nitriles via 1,2-arynes is reported. Aryl- and hetaryl nitriles, cyanamides, and trimethylacetonitrile gave phenanthridine products. The method was extended to provide bisphenanthridine 10 by a one-pot bis-cyclization, using 1,3-dicyanobenzene and PhF in 1:5 ratio. Reaction of 1-fluoronaphthalene and 4-chlorofluorobenzene with benzonitrile afforded the regioisomerically pure products 11 and 12, respectively.     

A one-pot access to pyridine/benzo fused cyclododecanes via multi-component tandem reactions

A facile syntheses of novel poly-substituted pyridine/benzo fused cyclododecane hybrid heterocycles have been achieved through one-pot multi-component tandem strategy employing cyclododecanone, aromatic aldehydes and malononitrile.     

A new practical one-pot access to sulfonimidates

Sulfonimidates were prepared from sulfinamides and iodosobenzene in a very mild one-pot procedure in good to excellent yields. This reaction allows quick and efficient access to a class of molecules of important synthetic as well as biological and industrial interest. [reaction: see text]     

Indium-mediated one-pot three-component reaction of aromatic amines, enol ethers, and allylic bromides

[reaction: see text] A new and efficient indium-mediated one-pot three-component reaction for the synthesis of N-aryl-substituted homoallylamines from aromatic amines, enol ethers, and allylic bromides in THF at room temperature is described.     

A convenient access to 2,4-disubstituted quinazolines via one-pot three-component reaction under mild conditions†

Abstract

A new and practical method has been developed for the synthesis of 2,4-disubstituted quinolines via one-pot three-component reaction of o-amino arylketones, aldehydes and ammonium acetate in high yields by using DDQ in CH₃CN under mild conditions. Neutral conditions, atom economy, easy work-up procedures and compatible with different functional groups are the salient features of this protocol.     

A telluride-triggered nucleophilic ring opening of monoactivated cyclopropanes

[reaction: see text] Acylcyclopropanemethanol tosylates undergo rapid ring opening at room temperature by the action of lithium telluride to produce the enolate of a homoallylic ketone. The enolate can be protonated to yield the corresponding ketone or treated with benzaldehyde to give the aldol product with good syn or anti diastereoselectivity depending on the conditions.     

Zirconium-mediated SN2' substitution of allylic ethers: regio- and stereospecific formation of protected allylic amines

A new zirconium-mediated, regio- and stereospecific SN2' substitution of allylic ethers with a nitrogen nucleophile has been developed. Cbz-protected amine products were isolated in high yield from reactions with a wide range of Z allylic ethers. A mechanism of the allylic substitution consistent with the results of the kinetics and kinetic isotope effect studies was proposed.     

Access to chiral homoallylic vicinal diols from carbonyl allylation of aldehydes with allyl ethers via palladium-catalyzed allylic C-H borylation

Chiral homoallylic vicinal diols are found in many bioactive compounds and are among the most versatile functional groups in organic chemistry. Here, we describe an asymmetric carbonyl allylation of aldehydes with allyl ethers proceeding via allylic C-H borylation enabled by palladium and chiral phosphoric acid sequential catalysis, providing facile access to homoallylic vicinal anti-diols in high yields and with excellent stereoselectivity. This protocol enables the total synthesis of aigialomycin D to be finished within 7 steps.     

A multi-component domino reaction for the direct access to polyfunctionalized indoles via intermolecular allylic esterification and indolation

A novel multi-component reaction for the synthesis of polyfunctionalized indoles and bis-indoles has been established. The reaction pathways were controlled by varying enamines with different substitution patterns to give polyfunctionalized indoles and bis-indoles selectively. The reaction proceeds at a fast speed within 15-30 min with water as the major byproduct, which makes work-up convenient.     

New access to H-phosphonates via metal-catalyzed phosphorus-oxygen bond formation

A novel approach to H-phosphonates from hypophosphorous acid using a transfer hydrogenation process was developed. This method is atom-economical, environmentally friendly, catalytic, and efficient, leading easily to H-phosphonate monoesters or ammonium salt in moderate to good yields.     

Vilsmeier-type reaction of dimethylaminoalkenoyl cyclopropanes: one-pot access to 2,3-dihydrofuro [3,2-c]pyridin-4(5H)-ones

A domino reaction of readily available 1-carbamoyl-1-dimethylaminoalkenoylcyclopropanes in the presence of triflic anhydride (Tf(2)O) in N,N-dimethylformamide (DMF) is described, which provides a facile one-pot access to 2,3-dihydrofuro[3,2-c]pyridin-4(5H)-ones via tandem formylation (Vilsmeier-type reaction), intramolecular cyclization, and ring-enlargement sequences.     

Stereoselective synthesis of cyclic ethers via bromine assistedepoxide ring expansion

9-Oxabicyclo[6.1.O]non-4-ene reacts with bromine to give stereoselectively trans, trans-2,6-dibromo-9-oxabicyclo[3.3.1]nonane and trans, trans-2,5-dibromo-9-oxabicyclo[4.2.1]nonane.