AbstractThe chloro alcohols4–6derived from TADDOLs (=α,α,α′,α′‐tetraaryl‐1,3‐dioxolan‐4,5‐dimethanols) are used to prepare corresponding sulfanyl alcohols, ethers, and amines (Scheme 1andTable 1). The dithiol analog of TADDOL and derivatives thereof,45–49, were also synthesized. The crystal structures of 16 representatives of this series of compounds are reported (Figs. 1–3andScheme 2). The thiols were employed in Cu‐catalyzed enantioselective conjugate additions ofGrignardreagents to cyclic enones, with cycloheptenone giving the best results (er up to 94 : 6). The enantioselectivity reverses fromSi‐addition with the sulfanyl alcohol toRe‐addition with the alkoxy or dimethylamino thiols (Table 4). CuI‐Thiolates,50–53, could be isolated in up to 84% yield (Scheme 2) and were shown to have tetranuclear structures in the gas phase (by ESI‐MS), in solution (CH2Cl2, THF; by vapor‐pressure osmometry and by NMR pulsed‐gradient diffusion measurements;Table 5), and in the solid state (X‐ray crystal structures inScheme 2). The Cu complex50of the sulfanyl alcohol is stable in air and in the presence of weak aqueous acid, and it is a highly active catalyst (0.5 mol‐%) for the 1,4‐additions, leading to the same enantio‐ and regioselectivities observed with thein situgenerated catalyst (6.5 mol‐%;Scheme 3). Since the reaction mixtures contain additional metal salts (MgX2, LiX) it is not possible at this stage, to propose a mechanistic model for the conjugate additions.