The first total synthesis of lasubine I and I1 and subcosine I has been achieved. A crucial step of this synthesis involves thermal [3+ 21 dipolar cycloaddition of 1-(3, 4- dimethoxyphenyl) butadiene with 2, 3, 4, 5-tetrahydropyridine 1-oxide, affording the E and 2 isomers of 2-(3, 4-dimethoxystyryl)-2, 3, 3a, 4, 5, 6-hexahydrop~ rolo [1, 2-b] isoxazole favoring the exo adduct in each case. On treatment with hydrogen chloride followed by ...
