627862-69-5Relevant academic research and scientific papers
Highly enantioselective catalytic cross-dehydrogenative coupling of n -carbamoyl tetrahydroisoquinolines and terminal alkynes
Sun, Shutao,Li, Chengkun,Floreancig, Paul E.,Lou, Hongxiang,Liu, Lei
supporting information, p. 1684 - 1687 (2015/04/14)
The first catalytic asymmetric cross-dehydrogenative coupling of cyclic carbamates and terminal alkynes has been established. The reaction features high enantiocontrol and excellent functional group tolerance and displays a wide range of structurally and electronically diverse carbamates as well as terminal alkynes. N-Acyl hemiaminals were identified as the reactive intermediates through preliminary control experiments. Employing readily removable carbamates as substrates rather than traditionally adopted N-aryl amines allows applications in complex molecule synthesis and therefore advances the C-H functionalization strategy to a synthetically useful level.
Enantioselective total syntheses of the Ipecacuanha alkaloid emetine, the Alangium alkaloid tubulosine and a novel benzoqainolizidine alkaloid by using a domino process
Tietze, Lutz F.,Rackelmann, Nils,Mueller
, p. 2722 - 2731 (2007/10/03)
The first enantioselective syntheses of the Ipecacuanha alkaloid emetine (1) and the Alangium alkaloid tubulosine (2) is described employing a domino Knoevenagel/hetero-Diels-Alder reaction and an enantioselective catalytic transfer hydrogenation of imines as key steps. Thus, hydrogenation of the imine 15 with the catalyst (R,R)-16 gives the tetrahydroisoquinoline 14 with 95% ee which was transformed into the aldehyde (1S)-7. The three-component domino reaction of (1S)-7 with 6 and 8 led to 19, which in a second domino process was treated with K2CO3 in methanol followed by a hydrogenation to give the benzoquinolizidine 4 together with the diastereomers 22 and 23 in a overall yield of 66%. Further transformation of 4 with the amines 3 and 5 yielded enantiopure emetine (1) and tubulosine (2), respectively. In addition, starting from 19 the novel benzoquinolizidine alkaloid 34 was synthesised; this compound resembles the vallesiachotamine alkaloid dihydroantirhin 31, which has not been isolated so far but probably must also exist in nature.
Catalyst-controlled stereoselective combinatorial synthesis
Tietze, Lutz F.,Rackelmann, Nils,Sekar, Govindasamy
, p. 4254 - 4257 (2007/10/03)
Stereochemical diversity as a novel concept in combinatorial chemistry for the synthesis of nonpeptidic biologically active compounds is introduced. As an example, the combination of the hydrogenation of imines in the presence of either enantiomer of a ch
