STRUCTURE OF (2'R-STAR,5S-STAR)-(+/-)-5-(TETRAHYDRO-2'H-PYRAN-2'-YL)-2(5H)-FURANONE

C9H12O3, M(r) = 168.2, triclinic, P1BAR, a = 5.5385 (6), b = 8.543 (1), c = 10.373 (1) angstrom, alpha = 113.329 (9), beta = 100.78 (1), gamma = 99.82 (1)-degrees, V = 426.2 (2) angstrom 3, D(x) = 1.31 g cm-3, Z = 2, Cu K-alpha (lambda = 1.54178 angstrom, graphite monochromator), mu = 8.2 cm-1, F(000) = 180, T = 293 K. Final R = 0.036, wR = 0.081 for 1559 reflections with I > 3-sigma(I). The relative configurations at the two chiral centers are (S,R). The dihedral angle between the five- and six-membered rings (O1-C4-C5-O3) is 69.9 (1)-degrees. The tetrahydropyran is in a chair conformation with the furanone ring equatorial.