Study On The Synthesis Of Heterocycles By Palladium Or Copper-catalyzed Cyclizations

Transition metal-catalyzed coupling reaction has emerged as one of the mostpowerful tools for C-C and C-hetero atom (S, N, O) bond formation in organicchemistry. This method could construct sulfur, nitrogen, oxygen-containingheterocyclic compounds from readily accessible starting materials under mildconditions with high selectivity. Benzo[b]thiophenes, isoquinolines andbenzo[b]oxepines are widely existed in pharmaceutical molecules and functionalmaterials. They are the core unit of numerous biological properties natural products. Asa consequence, the synthesis of these privileged structures has recently attracted muchattention and more efficient methods are being developed. This thesis focused on thesynthesis of heterocyclic compounds catalyzed by palladium or copper catalyst. Themain contents are listed as follow:(1) A copper-catalyzed thiolation annulation reaction of2-bromoalkynylbenzeneswith sodium sulfide has been developed for the synthesis of benzothiophenes. Both ofcopper catalysts and sulfur reagent are cheap and low toxicity. The reaction wasconducted under mild conditions.(2) A palladium-and copper-catalyzed tandem C-N/C-C bond forming reactionhas been developed, which leads to trifluoromethyl substituted indolo-andpyrrolo[2,1-a]isoquinolines. This protocol could be served as synthetic applications oftrifluoromethyl-containing building blocks and also provide a new and useful strategy for constructing isoquinoline ring.(3) A copper-catalyzed tandem C-C/C-O bond forming reaction oftrifluoromethyl-containing ortho-halo-chlorostyrenes with ketones has been developedfor the synthesis of4-trifluoromethyl benzoxepines. The reaction was conductedunder simple conditions with moderate to good yields.