39964-92-6Relevant articles and documents
Synthesis of 1,2-Dihydroisoquinolines by a Modified Pomeranz-Fritsch Cyclization
Ji, Xiang,Huang, Zheng,Lumb, Jean-Philip
, p. 1062 - 1072 (2020/01/31)
Isoquinolines (IQs) and their derivatives are present in many natural products and biologically active small molecules. Herein, we report a modified procedure for the classical Pomeranz-Fritsch protocol, which expands the scope of 1,2-dihydroisoquinoline (DHIQ) products. 1,2-DHIQs are an attractive branch point for the synthesis of IQs, but because of their innate reactivity, they have remained difficult to prepare. We demonstrate that the Fujioka/Kita conditions, combining trimethylsiyltriflate (TMSOTf) and an amine base, activate dimethylacetals required for Pomeranz-Fritsch cyclization under sufficiently mild conditions to prepare a broad range of 1,2-DHIQ products. We also demonstrate the synthetic value of these DHIQs by further functionalization to either reduced tetrahydroisoquinoline (THIQ) or fully aromatized IQ natural products.
LiCl-mediated preparation of highly functionalized benzylic zinc chlorides
Metzger, Albrecht,Schade, Matthias A.,Knochel, Paul
supporting information; experimental part, p. 1107 - 1110 (2009/04/06)
In the presence of zinc dust (1.5-2.0 equiv) and LiCI(1.5-2.0 equiv), various benzylic chlorides bearing functional groups (iodide, cyanide, ester, ketone) are smoothly converted at 25°C to the corresponding zinc reagents without homo-coupling (≤5%). The utility of these benzylic zinc reagents is demonstrated by a short synthesis of papaverine.