Kaija Sipilä

SYNTHESIS OF 9-ALKYL- AND 9-ARYLTHIOPHENANTHRENES

Abstract A simple method for the preparation of 9-alkyl- and 9-arylthio-phenanthrenes from 9-bromophenanthrene and a thiol is described.

Diastereoselectivity in Reactions of Lithiated 2-Phenylthiomethylthiotetrahydropyrans

Diastereoselectivities of up to 95:5 in alkylations of lithiated O,S,S-acetals are rationalized by the locked conformation of the five-membered ring caused by lithium-to-oxygen coordination. The relative configurations of the two diastereomers obtained in benzylation of lithiated 2-(phenylthiomethylthio)tetrahydropyran were confirmed by comparison with reference compounds of known stereochemistry obtained by benzylic reduction of crystalline hydroxyalkylated derivatives.

(1S,2R,2′S)- and (1S,2S,2′S)-1-phenyl-2-phenyl­thio-2-(tetra­hydro­pyran-2′-yl­thio)­ethanol diastereoisomers at 193 K

In the synthesis of 1-phenyl-2-phenylthio-2-(tetrahydropyran-2-ylthio)ethanol, C(19)H(22)O(2)S(2), four diastereoisomers are formed. Two non-centrosymmetric enantiomeric forms which crystallize in space groups P2(1)2(1)2(1) and Pna2(1) are presented. The former has an intramolecular hydrogen bond between the hydroxyl group and the O atom of the tetrahydropyran ring. In the latter isomer, the hydroxyl group forms an intermolecular hydrogen bond to the O atom of the tetrahydropyranyl group of a neighbouring molecule, joining the molecules into chains in the c-axis direction; the O.O distances are 2.962 (4) and 2.764 (3) A, respectively. The tetrahydropyran rings are in chair conformations in both isomers and the S side chain has an equatorial orientation in the former, but an axial orientation in the latter molecule.

Di-9-anthryl disulfide at 193 K

The title compound, C28H18S2, crystallizes in the monoclinic space group P21/n and the structure shows pseudosymmetry close to the space group C2/c. At 193 K the compound has a long S—S bond of 2.1089 (12) A and the S atom to anthracene bond distances are 1.776 (3) and 1.770 (2) A. The C—S—S—C torsion angle is 76.06 (13)°.

Two 9-alkylthiophenanthrenes at 193 K (alkyl = dodecyl and tetradecyl)

Two isostructural 9-thiophenanthrene derivatives, 9-dodecylthiophenanthrene, C 26 H 34 S, (I), and 9-tetradecylthiophenanthrene, C 28 H 38 S, (II), are reported. They crystallize in the monoclinic space group P2 1 /c with four molecules in a unit cell. The S-C phenanthrene bonds are 1.767 (2) and 1.772 (4) A and S-C alkyl bonds are 1.809 (2) and 1.804 (4) A for (I) and (II), respectively. The bond angles at S are 104.04 (11) and 104.0 (2)° for (I) and (II), respectively.

Stereochemical Studies on Four Diastereoisomers of 1-Phenyl-2-Phenylthio-2-(2-Tetrahydropyran-2-Ylthio)Ethanol, C19H22O2S2

Stereochemistry of the diastereoisomers of the title compound and comparison to its propanol derivative are discussed.