(R)-2-[(R)-2,2-Dimethyl-1,3-dioxolan-4-yl]-1,3-oxathio-lan-5-one.

In the title compound, C(8)H(12)O(4)S, the two five-membered rings both adopt envelope conformations. In the crystal, weak C-H⋯O inter-actions link neighbouring mol-ecules.

4,5,6-Tri-O-acetyl-2,3-di-S-ethyl-2,3-dithio-d-allose diethyl dithio-acetal.

The title compound, C(20)H(36)O(6)S(4), was obtained by ethanethiol-ysis of 3,5,6-tri-O-acetyl-1,2-O-isopropyl-idene-α-d-gluco-furan--ose. One of the ethyl groups is disordered over two sites with refined occupancies of 0.869 (6) and 0.131 (6). Compared with the precursor, the absolute configuration of the stereocenters at positions C-3 and C-2 are inverted and maintained, respectively.

2-Methyl-1,1,3,3-tetra-phenyl-propan-2-ol.

The title compound, C(28)H(26)O, was synthesized by condensation of diphenyl-methyl-lithium and ethyl acetate. In one diphenyl-methyl group, the two benzene rings are rotated by 65.0 (3)° with respect to each other, while in the other diphenyl-methyl group, the dihedral angle between the two benzene rings is 84.1 (3)°.