The synthesis of thiophenium and of oxazolium salts from diazoketones

Abstract

4-Diazoacetylthianthren with perchloric acid in acetonitrile gave 2-oxo-1,2-dihydrothieno[3,2,1 -de] -thianthrenium perchlorate which gave the corresponding enol ether with diazomethane. This ether was compared with 3-methoxy-1 -methylbenzo[b]thiophenium perchlorate, prepared from 3-methoxythiophen, and which was much more stable to solvolysis than the demethoxy-analogue. In contrast to the 4-diazoacetylthianthren, 7diazoacetyl-2-methylbenzo[b]thiophen with acetonitrile and perchloric acid cyclised in an alternative mode to give a new synthesis of 2-methyl-4-substituted oxazolium perchlorates.

New Efficient Nickel-Catalyzed Cross-Coupling Reaction between Two Csp3Centers

“…Starting Materials. The following starting materials were prepared according to literature procedures: 5-iodo-3-phenyl-1-pentene ( 20a ),14a ( E )-ethyl 6-iodo-2-hexenoate ( 20c ),14b ( E )-ethyl 7-iodo-2-heptenoate ( 20d ),14b ( E )- tert -amyl 7-iodo-2-heptenoate ( 20e ),8e 3-iodopropanenitrile ( 23a ),17a 4-iodobutanenitrile ( 23b ),17b 5-iodopentanenitrile ( 23c ),17c 3-iodo-1-phenyl-1-propanone ( 26a ), 4-iodo-1-phenyl-1-butanone ( 26b ), 6-iodohexyl pivalate ( 26f ), 4-iodo-1-(2-thienyl)-1-butanone ( 26h ), ethyl 3-iodopropanoate ( 26j ), 2-(2-iodoethyl)-2-methyl-1,3-dithiolane ( 26k ), 3-iodopropyl phenyl sulfide ( 26l ), 5-iodopentyl pivalate ( 26m ), benzyl 3-iodopropanoate ( 26n ), 4-iodobutyl pivalate, 3-iodopropyl pivalate, 5-iodopentyl acetate, 3-chloro-1-piperidino-1-propanone, 4-(4-chlorobutanoyl)benzonitrile, and 1-chloro-4-octanone …”