A green chemical method for mild oxidation of 1,2,3,4-tetrahydroisoquinolines (THIQs) and 3,4-dihydroisoquinolines (DHIQs) has been developed using air (O 2 ) as a clean oxidant. DHIQs and THIQs could be efficiently oxidized to isoquinolines in dimethyl sulfoxide at 25 °C under an open air atmosphere with CuBr 2 (20 mol %) as the catalyst; different bases [NaOEt and/or 1,8-diazabicyclo[5,4,0]undec-7-ene] were used for the reaction according to the patterns of substituents (R 1 , R 2 ).

Improved stereoselective syntheses of the target compounds (＋)-valiolamine 1 and (＋)-valienamine 2 starting from naturally abundant (-)-shikimic acid are described. A common key intermediate compound 7 was first synthesized from (-)-shikimic acid in 9 steps. The compound 7 was then converted to (＋)-valiolamine 1 in 3 steps, and was also converted to (＋)-valienamine 2 in 4 steps. In summary, (＋)-valiolamine 1 and (＋)-valienamine 2 were synthesized from (-)-shikimic acid in 12 (or 13) steps in 40% and 39% overall yields, respectively. The present syntheses are more practical and might be important for the potential industrial preparations of pharmaceutically valuable (＋)-valiolamine 1 and (＋)-valienamine 2.

Novel total syntheses of oxoaporphine alkaloids such as liriodenine, dicentrinone, cassameridine, lysicamine, oxoglaucine and O-methylmoschatoline were developed. The key step of these total syntheses is Cu-catalyzed conversion of 1-benzyl-3,4-dihydro-isoquinolines (1-Bn-DHIQs) to 1-benzoylisoquinolines (1-Bz-IQs) via tandem oxidation/aromatization. This novel Cu-catalyzed conversion has been studied in detail, and was successfully used for constructing the 1-Bz-IQ core.

Novel stereoselective syntheses of N-octyl-β-valienamine (NOV) 1 and N-octyl-4-epi-β-valienamine (NOEV) 2 starting from naturally abundant (−)-shikimic acid are described in this article.

A novel Cu(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)–H bonds adjacent to 1-Bn-DHIQs was developed. This method was successfully applied in the first total synthesis of canelillinoxine.