Synthesis of Isoquinolines through IrIII-Catalyzed C–H Activation/Annulation from Benzimidates with Hydroxylisopropylalkynes
An IrIII-catalyzed cascade reaction consisting of C–H activation/annulation of benzimidates with hydroxylisopropylalkynes is reported. A broad range of isoquinolines has been prepared in one step with good functiona-group tolerance and high eff
Highly Efficient Synthesis of Multi-Substituted Allenes from Propargyl Acetates and Organoaluminum Reagents Mediated by Palladium
A simple and mild catalytic S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents is reported. The S N 2′ substitution reaction of propargyl acetates with organoaluminum reagents mediated by Pd(PhP 3) 2 Cl 2 (1 mol%)/PPh 3 (2 mol%)/K 2 CO 3 in tetrahydrofuran at 60 °C for 3-4 hours afforded the corresponding multi-substituted allenes in good yields (up to 94%) with high selectivities (up to 99%). The process was simple and easily performed, which offers an efficient method to synthesize the multi-substituted allene derivatives.
An approach to the selenobromination of aryl(thienyl)alkynes: Access to 3-bromobenzo[b]selenophenes and selenophenothiophenes
A novel approach for the cyclization of arylalkynes with selenium(IV) bromide prepared in situ has been elaborated. The use of an alkene additive as a bromine scavenger provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes. Reactions can be performed open to air without the use of moisture-sensitive reagents, anhydrous solvents, or an inert atmosphere. Selenobromination of ethynylthiophenes has been applied for the preparation of selenopheno[3,2-b]- and selenopheno[2,3-b]thiophenes. The molecular structures of representative derivatives have been confirmed by X-ray crystallographic analysis. The use of an alkene additive as a bromine scavenger under selenobromination conditions provides a convenient synthetic pathway for the synthesis of a wide variety of 3-bromobenzo[b]selenophenes in moderate to high yields. The reactions are not moisture-sensitive and do not require an inert atmosphere. Selenobromination of ethynylthiophenes enables the preparation of selenopheno[b]thiophenes. Copyright
Paegle, Edgars,Belyakov, Sergey,Arsenyan, Pavel
supporting information
p. 3831 - 3840
(2014/06/24)
Efficient synthesis of maleimides and carbazoles via Zn(OTf) 2-catalyzed tandem annulations of Lsonitriles and allenic esters
Lewis acid Zn(OTf)2-catalyzed tandem annulations of isonitriles and allenic esters which lead to efficient and flexible syntheses of a range of biologically significant maleimides and carbazoles and related compounds are reported. A mechanistic rationale is proposed to account for the observed reactivity.
An improved procedure for the preparation of aryl- and hetarylacetylenes
A number of relatively volatile acetylenes RC ≡ CH (R = aryl or hetaryl) have been prepared with high yields by heating a mixture of the corresponding alcohols RC ≡ CC(CH3)2OH and paraffin oil with small amounts of powdered potassium hydroxide in vacuum. The alcohols were obtained by Pd/Cu-catalyzed cross coupling of aryl or hetaryl halides RX (X = Br, in one case I) with the commercially available HC ≡ CC(CH3)2OH.
Mal'Kina,Brandsma,Vasilevsky,Trofimov
p. 589 - 590
(2007/10/03)
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