(+)-(1S,5R,10S)-11,11-Dimeth-yl-4-oxa-tricyclo-[8.4.0.0]tetra-deca-ne-3,12-dione

Abstract

The title compound, C(15)H(22)O(3), was prepared via amino-acid-promoted Robinson annulation followed by tandem Pd/C-mediated hydrogenation and oxidative cyclization. This product was instrumental in determining the feasibility of a stereocontrolled hydrogenation in which the directing hydroxyl group is adjacent to the 6-7-ring network and its olefinic component. The asymmetric unit consists of a single mol-ecule with normal geometric parameters. The absolute configuration was assigned based on the known enanti-omeric prescursor. Inter-molecular C-H⋯O inter-actions link each mol-ecule with four neighboring mol-ecules.

Fig. 1.

Chemical schemes for (I), (II), (III), and (IV). Hydrogen atoms are not shown

Fig. 2.

Chemical schemes for (V), (VI), (VII), and (VIII). Hydrogen atoms are not shown

Fig. 3.

Chemical schemes for (IX), (X), (XI), (XII), and (XIII).

Fig. 4.

The molecular structure is drawn with 50% probability displacement ellipsoids for the non-hydrogen atoms. The hydrogen atoms are drawn with an artificial radius.

Fig. 5.

A portion of the intermolecular hydrogen bond network. The symmetry operations for the molecules related to the central molecule are as follows: A: y, -x + y+1, 1/6 + z; B: x-y + 1, x, z - 1/6; C: y + 1, -x + y+1, 1/6 + z; D: x-y, x - 1, z - 1/6.