Efficient access to chiral trans-2,6-dialkyl-1,2,5,6-tetrahydropyridines via allylation of chiral imines and ring-closing metathesis
摘要:
Enantiomerically pure trans-2,6-dialkyl-1,2,5,6-tetrahydropyridines are synthesized in five steps from Garner's aldehyde in 37-44% overall yield. This strategy is based on the allylation of chiral iminoalcohols formed in situ followed by a ring-closing metathesis. (C) 2002 Elsevier Science Ltd. All rights reserved.
A Novel Route to Chiraltrans-6-Alkyl-2-hydroxymethyl-1,2,5,6-tetrahydropyridines by Allylation of Chiral Imines and Ring-Closing Metathesis− Total Synthesis of (−)-3-epi-Deoxoprosopinine
Chiral β-aryl-α,β-unsaturated amino alcohols were synthesized via a Pd-catalyzed asymmetric allylic amination of 4-aryl-1,3-dioxolan-2-one using planar chiral 1,2-disubstituted ferrocene-based phosphinooxazolines as ligands. Under the optimized reaction conditions, a series of substrates were examined and the products were obtained in good to excellent yields (up to 92%) and enantioselectivities (up to 98% ee) under mild reaction conditions. The desired products were determined to be of (R)-configuration and could subsequently be transformed into compounds with interesting biological activity using simple transformations.