Highly selective Diels-Alder reactions of dienophiles with 1, 3-cyclohexadiene mediated by Yb(OTf)(3).2H(2)O and ultrahigh pressures.

ABSTRACT

[reaction see text] Ultrahigh pressures and catalytic Yb(OTf)(3).2H(2)O were found to mediate Diels-Alder reactions of various electron-deficient dienophiles with 1,3-cyclohexadiene to produce endo-bicyclo[2.2. 2]oct-2-enes in moderate to excellent yield and selectivity. The proposed total synthesis of hapalindole Q based on bicyclo[2.2. 2]oct-2-ene construction by Diels-Alder reaction and subsequent olefin cleavage is outlined. Preliminary results demonstrating the viability of this strategy are presented.