Crystal structure of (±)-(3aR,5R,8bR)-5-hydroper-oxy-2-phenyl-6-tosyl-4,5,6,8b-tetra-hydro-pyrrolo-[3,4-e]indole-1,3(2H,3aH)-dione.

The title compound, C23H20N2O6S, crystallizes as a racemate in the space group P-1, with an overall L- or J-shape to each mol-ecule. Centrosymmetric pairs of mol-ecules are tandem hydrogen bonded between the hydro-per-oxy H atom and carbonyl O atom. A different centrosymmetric pairing has stacked S-tolyl rings, and a third pairing is L,J-inter-locked by the short leg. Except for stacked tolyl pairs, neighboring π-systems are much closer to orthogonal than coaxial. The title compound is the first example of a hydro-peroxide obtained from the autoxidation of a Diels-Alder adduct of a 2-vinyl-pyrrole.

A Lewis acid-catalyzed formal [3 + 3] cycloaddition of alpha,beta-unsaturated aldehydes with 4-hydroxy-2-pyrone, diketones, and vinylogous esters.

[reaction: see text] A Lewis acid-catalyzed formal cycloaddition of alpha,beta-unsaturated aldehydes with 6-methyl-4-hydroxy-2-pyrone, 1,3-diketones, and vinylogous silyl esters is described here.