organic compounds
Open access
(4R)-4-Benzyl-3-{(4S)-4-chloro-4-[(S)-2,2-dimethyl-1,3-dioxolan-4-yl]butanoyl}-1,3-oxazolidin-2-one
The title compound, C19H24ClNO5, was synthesized and subsequently employed in an Evans alkylation. The purpose was to prove the absolute configuration in the projected synthesis of the side chain of (-)-Lytophilippine A. The oxazolidinone and the isopropylidene acetal rings have twisted conformations. The oxazolidinone and side-chain carbonyl groups are orientated in an antiperiplanar arrangement to minimize van der Waals repulsions. Furthermore, the Cl atom and the acetonide-protected secondary alcohol are also in an antiperiplanar arrangement with a torsion angle of 173.64 (14)°. The absolute configuration was determined and agrees with the configuration of the used chiral auxiliary.
organic compounds
Open access
In the title compound, C21H18Si, the coordination geometry around the Si atom is a slightly distorted tetrahedron with C-Si-C angles in the range 106.05 (11) to 110.58 (10) ° and Si-C bond lengths in the range 1.855 (2) to 1.883 (3) Å. The alkyne C-C bond length is 1.167 (4) Å. The dihedral angles between the three phenyl rings are 63.89 (7), 86.38 (7) and 70.51 (8)°. In the crystal, molecules interact only by van der Waals forces.