Phenylfuran-based

A similar methodology was applied by the same group to the preparation of novel phenylfuran-based cyanohydrin esters by using Pseudomonas cepacia lipase and vinyl butanoate as the acylating agent. The results are summarised in Scheme 3.25. 

Paizs C, Tahtinen P, Lundell K, Poppe L, Irimie F-D, Kanerva LT. Preparation of novel phenylfuran-based cyanohydrin esters hpase-catalysed kinetic and dynamic resolution. Tetrahedron Asymm. 2003 14 1895-1904. 

Other classical synthetic approaches to 2-furanamine have failed, including the Curtius method and Beckmann rearrangement of 2-benzoylfuran oxime. However, hydrazinolysis of AT-(2-furyl)phthalimide, obtained from phthalimide and 2,5-dimethoxy-2,5-dihy-drofuran, gives 2-furanamine which was not isolated but detected by GLC-MS and H NMR spectroscopy. The latter reveals the absence of imino tautomers (75AP713). The chemistry of 2-dialkylamino-5-phenylfurans is typical of enamines protonation occurs on carbon to produce iminium salts. They are stable to base but afford 5-phenylfuran-2(3//)-one on hydrolysis with dilute acid. 2-Morpholino-5-phenylfuran couples with diazonium salts and affords Diels-Alder adducts with maleic anhydride and IV-phenylmaleimide (73JCS(P1)2523). 

The failure to obtain such a furan adduct from an aryne precursor which yields other aryne-diene adducts (148) does not necessarily indicate the absence of arynes, however. One example of precisely this phenomenon was traced to the unique ability of furan to preferentially consume the aryne precursor 411 in a nonaryne pathway leading to 2-phenylfuran (172). Other examples are due to the instability of the benzyne-furan adduct 148a to strong bases. ... 

Ethyl diazoacetate added dropwise during ca. 7.5 hrs. with stirring at 90° under Ng to a mixture of 1-phenylpropyne, anhydrous cupric sulfate, and cyclohexane, the temp, reduced to 70° after Ng-evolution has started 5-ethoxy-2-methyl-3-phenylfuran. Y 48% based on 1-phenylpropyne consumed. I. A. D ya-konov and M, I. Komendatov, 7K.. 31, 3881 (1961) G. A. 57, 8405f benzyne as dipolarophile s. R. Huisgen and R. Knorr, Naturwissenschaften 48, 716 (1961). 

Using the nuclear-ensemble approach, we have simulated the absorption spectra of benzene, fiiran and 2-phenylfuran in gas phase. Based on these simulations, experimental vertical excitations were estimated. For the three molecules, the main bands were assigned and the spectrum-decomposition method was applied to 2-phenylfuran. 

Spectrum simulations were based on TDDFT with the CAM-B3LYP functional. Methodological comparisons with RI-CC2 and other methods showed that TD-CAM-B3LYP have a very good performance for furan, 2-phenylfuran and the bright band of benzene. Substantial energy shifts, however, were observed for the dark bands of benzene. 

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