Absolute configuration of C23H34O8Si, the product of an asymmetric synthesis involving the Rh(II) catalyzed reaction of a chiral vinyldiazomethane with methyl-2-methyl-3-furoate

The compound under investigation crystallizes in the noncentrosymmetric ort horhombic space group P2(1)2(1)2(1) with a = 7.9358(11), b = 11.0532(13), c = 29.2425(43) Angstrom, volume = 2565.0(6) Angstrom(3), and Z = 4. The C23 H34O8Si molecule contains three chiral centers tone of which is of known co nfiguration, based upon an (R)-pantolactone auxiliary group). We have deter mined the absolute configuration of this species (via the anomalous dispers ion of Si relative to C and O) and show that it is consistent with the know n configuration of the (R)pantolactone moiety.