Synthesis of Isocoumarins and α-Pyrones via Electrophilic Cyclization
摘要:
A variety of substituted isocoumarins and alpha-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICI, I-2, PhSeCl, p-O2NC6H4SCl, and HI. This methodology accommodates various alkynyl esters and has been successfully extended to the synthesis of polycyclic aromatic and biaryl compounds.
Divergent syntheses of iodinated isobenzofuranones and isochromenones by iodolactonization of 2-alkynylbenzoic acids in ionic liquids
作者:Raffaella Mancuso、Christian C. Pomelli、Francesco Malafronte、Asif Maner、Nadia Marino、Cinzia Chiappe、Bartolo Gabriele
DOI:10.1039/c7ob00962c
日期:——
2-alkynylbenzoic acids, carried out at 100 °C in ionicliquids (ILs) as unconventional solvents and with molecular iodine as the iodine source, in the absence of external bases, was found to be strongly dependent on the nature of the IL medium. In particular, while the use of N-ethyl-N-methylmorpholinium dicyanamide (Mor1,2N(CN)2) promoted the stereoselective formation of (E)-3-(iodomethylene)isobenzofuran-1(3H)-ones
Regioselective Synthesis of (E)-5-(Tributylstannylmethylidene)-5H-furan-2-ones and (E)-3-(Tributylstannylmethylidene)-3H-isobenzofuran-1-ones: Easy Access to γ-Alkylidenebutenolide and Phthalide Skeletons
Regio- and stereoselective synthesis of γ-alkylidenebutenolides and γ-alkylidenephthalides has been achieved through the palladium-catalysed tandem cross-coupling/cyclisation reactions of tributylstannyl-3-iodopropenoate or the 2-iodo benzoate derivatives with tributyltinacetylene. Iododestannylation occurred with inversion of the configuration of the exocyclic double bond in the case of butenolides, but with retention of configuration for the phthalide. The selectivity observed in the Stille reaction was found to be dependent on the nature of the vinyl or the aryl halide.