Cross-dehydrogenative coupling ethers

Scheme 51 Cu-catalyzed cross-dehydrogenative coupling of (benzo)thiazoles with cyclic ethers.

The synthesis of a-acyloxy ethers (formation of C—O bonds) was achieved by the TBHP oxidation of a mixture of a carboxylic acid (R C02H, R =aryl, heteroaryl, alkyl) and an ether (R, R = alkyl, alkyl halide) in the presence of BU4NI as the catalyst. The transformation involved a cross-dehydrogenative coupling (CDC) reaction of the C-H bond. ... 

Copper-catalyzed cross-dehydrogenative coupling (CDC) reactions of (benzo)thiazoles 49 with cycHc ethers 50 have been developed under mild conditions (130L4600). Notably, the 2-thiazolyl acetals, known as the masked 2-thiazolecarboxaldehydes, could be successfully obtained by this CDC reaction. 

SCHEME 7. 26 Copper-catalyzed oxidative cross-dehydrogenative-coupling of 3-ketoesters or 2-carbonyl-substituted phenols with ethers. 

Copper-catalyzed dehydrogenative cross-coupling reactions of (benzo) thiazoles with cychc ethers 106 to give the products 107 have been developed by Jiang and Chen (Scheme 51) (20120L4950, 20130L4600). A radical pathway was proposed for the reaction with cyclic ethers initiated... 

The experiments were conducted directly in the cavity of the EPR spectrometer [94]. Other reactions of note summarized in Table I include the decarboxylation of carboxylic acids ( 90% selectivity) [75, 88] the dehydrogenation of organonitriles, equation (24) [88], and the radical cross coupling observed when solutions of alkanes and ethers are simultaneously irradiated in the presence of Q4W10O32, equation (25) [75,90]. In equation... 

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