Bis-(1-chlor-3-phenoxy-prop-2-yl)-sulfane - Nucleophile Substitution und Regiochemie, Diastereomerentrennung und -zuordnung. Synthese diastereomerenreiner Trithiacyclen

Abstract

Bis‐(1‐chloro‐3‐phenoxy‐prop‐2‐yl)‐sulfanes – Nucleophilic Displacement and Regiochemistry. Separation and Assignment of Diastereomers. Synthesis of Diastereomerically Pure Trithiacycles The title compounds 1 were substituted by a series of O‐, N‐ and S‐nucleophiles (H2O solvolysis, AgOAc, NaN3, KSCN, NaSPh, thiourea). A strong tendency to β‐elimination of HCl depending on the kind of the attacking nucleophile was found. In most cases no regioisomerization could be detected in the isolated products of the nucleophilic displacement. Best results were obtained with sulfur nucleophiles. The separation of the diastereomeric mixture of the p‐kresyl derivative 1b into the individual diastereomers 1bA and 1bB in a preparative scale was achieved. These 3‐thia‐1,5‐dichlorides and several products of substitution could be assigned to the meso‐ or (±)‐form by examination of the stereochemistry and symmetry of the corresponding sulfoxides. The 1,5‐dimercapto derivatives 8 are convenient as structural units for the synthesis of diastereomerically pure cis‐ or trans‐disubstituted trithiacycles e.g. 15bA, 15bB. The (±)‐form of the 4,6‐disubstituted 2,5,8‐trithia[9]‐(2,6)‐pyridinophane 16bA was characterized by X‐ray crystal structure determination.