A palladium‐catalyzed tandem reaction of cyanomethyl benzoates with arylboronic acids has been achieved. Substitution at the 2‐position of cyanomethyl benzoates was found to be crucial for the selective synthesis of oxazoles and isocoumarins. Cyanomethyl benzoates afforded 2,4‐diaryloxazoles as products, while 2‐benzoyl‐substituted cyanomethyl benzoates delivered 3‐benzoyl‐4‐aryl‐isocoumarins selectively
Synthesis of 2,4-Disubstituted Oxazoles by a Copper-Catalyzed [3+2] Annulation/Olefination Cascade between Amides and IIII/PV Hybrid Ylides
作者:Zhaofeng Wang、Xingchen Ye
DOI:10.1055/a-2185-0673
日期:——
We report a novel and efficient method for oxazole synthesis through a copper-catalyzed [3+2] annulation/olefination cascade between readily available iodonium–phosphonium hybrid ylides and amides. An unprecedented α-phosphonium Cu carbenoid acts as the key intermediate. This method features excellent regioselectivity with mild reaction conditions and a broad substrate scope. Its synthetic utility
Unusual rearrangements of 2-aroylimidoyl-2-phenylethylidene to 2,5-disubstituted oxazoles
作者:Adrian D. Clark、Wit K. Janowski、Rolf H. Prager
DOI:10.1016/s0040-4020(98)01171-5
日期:1999.3
Flash vacuum pyrolysis of 2-aroyl-3-phenylisoxazol-5(2H)-ones leads to good yields of 2-aryl-4-phenyloxazoles, and smaller quantities of 2-aryl-5-phenyloxazoles and 5-aryl-2-phenyloxazoles. The mechanism of formation of the 2,5-disubstituted products has been investigated by C-13 and substituent labelling, and a non-statistical breakdown of a symmetrical intermediate is invoked to rationalise the product formation. (C) 1999 Elsevier Science Ltd. All rights reserved.
A novel synthetic method of 2,4-disubstituted oxazoles using carboxylic acid-derived Bu2Sn[OC(O)R]2
A novel synthetic method for the preparation of 2,4-disubstituted oxazoles was developed, entailing the reaction of dibutyltin diacylates Bu2Sn[OC(O)R](2) with 1-substituted acetylenes and TMSN3 to afford a range of 2,4-disubstituted oxazoles in good yields. (C) 2020 Elsevier Ltd. All rights reserved.
Synthesis of 2,4- and 2,4,5-substituted oxazoles via a silver triflate mediated cyclization