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Rasheed AhmadKhera Rasheed Ahmad Ihsan Ullah Obaid‐Ur‐Rahman Abid Olumide Fatunsin Muhammad Sher Alexander Villinger Peter Langer 《Helvetica chimica acta》2010,93(9):1705-1715
2‐Aryl‐2,3‐dihydro‐4H‐pyran‐4‐ones were prepared in one step by cyclocondensation of 1,3‐diketone dianions with aldehydes. The use of HCl (10%) for the aqueous workup proved to be very important to avoid elimination reactions of the 5‐aryl‐5‐hydroxy 1,3‐diones formed as intermediates. The TiCl4‐mediated cyclization of a 2‐aryl‐2,3‐dihydro‐4H‐pyran‐4‐one with 1,3‐silyloxybuta‐1,3‐diene resulted in cleavage of the pyranone moiety and formation of a highly functionalized benzene derivative. 相似文献
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Peter Oechsle Dr. Ulrich Flörke Dr. Hans Egold Prof. Dr. Jan Paradies 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18559-18563
Highly efficient, one‐step synthesis of sulfur‐containing heteroacenes was achieved through palladium‐catalyzed C?S cross‐coupling of bis‐alkynes with thioacetate as hydrogen sulfide surrogate. Heteroacenes consisting of three, five, and seven fused aromatic rings were obtained in a single catalytic step by four‐, six‐, and eightfold C?S bond formation. 相似文献
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Manganese(III)‐promoted cyclization of N‐alkenylmalonamides (=N‐alkenylpropanediamides) gave 3‐(aryl/(alkylamino)carbonyl) β‐lactams as well as 3‐(aryl/(alkylamino)thiocarbonyl) β‐lactams. The relative configuration of the obtained products was unambiguously determined by X‐ray crystallography. The proposed method is very useful for the one‐pot synthesis of a number of 3‐(aryl/(alkylamino)carbonyl) β‐lactams, especially those containing an amino(thiocarbonyl) moiety, which are not selectively accessible by other methods. 相似文献
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Marina Grinco Veaceslav Kulciţki Nicon Ungur Wieslaw Jankowski Tadeusz Chojnacki Pavel F. Vlad 《Helvetica chimica acta》2007,90(6):1223-1229
Methyl (2Z,6Z,10E,14E)‐ ( 3 ) and methyl (2E,6Z,10E,14E)‐geranylfarnesoate ( 4 ) were prepared, and then individually cyclized in the presence of the superacid FSO3H. In the case of substrate 3 , the scalaranic ester 9 (26%) and the cheilanthanic ester 10 (39%) were isolated. Under the same conditions, substrate 4 afforded a mixture of the corresponding stereoisomers 11 (25%) and 12 (63%). The observed product selectivity supports that the internal, (6Z)‐configured C?C bond in these and other biologically relevant substrates plays an essential role in the cyclization process. 相似文献