Four-Step One-Pot Catalytic Asymmetric Synthesis of Polysubstituted Tricyclic Compounds: Lipase-Catalyzed Dynamic Kinetic Resolution Followed by an Intramolecular Diels–Alder Reaction
Starting from readily available tertiary alcohols, four different reactions (a 1,3-migration of a hydroxy group, kinetic resolution, racemization, and an intramolecular Diels–Alderreaction) took place under co-catalysis by lipase and oxovanadium compounds in a one-pot process to produce polysubstituted tricyclic carbon frameworks in high yields and with high enantioselectivities. The key to the success
The protecting-group-freeasymmetrictotalsynthesis of (−)-rosmarinecine was achieved in only four steps from the commercially available (±)-3-hydroxypyrrolidine hydrochloride (2a). The key steps include the direct oxidation of (±)-2a to (±)-3-hydroxy-1-pyrroline N-oxide (1a) using the Davis reagent and the domino reaction; viz., the lipase-catalyzed dynamic kinetic resolution of (±)-1a with 1-ethoxyvinyl
Lipase-catalyzed domino kinetic resolution of α-hydroxynitrones/intramolecular 1,3-dipolar cycloaddition: a concise asymmetric total synthesis of (–)-rosmarinecine
作者:Shuji Akai、Kouichi Tanimoto、Yukiko Kanao、Sohei Omura、Yasuyuki Kita
DOI:10.1039/b419426h
日期:——
reactions were developed to directly provide tetrahydrofuro[3,4-c]isoxazole derivatives (5 and 9) in > or =90% ee from racemic alpha-hydroxynitrones (2 and 6), which were used in the concise asymmetrictotalsynthesis of (-)-rosmarinecine .