Preparation and use of chiral (Z)-enol ethers in asymmetric Bradsher cycloaddition

Article abstract of DOI:10.1016/0040-4039(96)01540-7

Chiral (Z)-enol ethers 7a-7p have been prepared in two steps. Bradsher cycloaddition between such compounds and 2,7-naphthyridinium salt 4b in water or in ter-butanol-water afforded, in some cases with good yield and diastereoselectivity, highly functionalized isoquinoline derivatives, potential intermediates in Manzamine A 1 total synthesis. X-Ray analysis secured the direction of asymmetric induction with enol ether 7l.