Copper(II)‐Catalyzed Hydrosilylation of Ketones Using Chiral Dipyridylphosphane Ligands: Highly Enantioselective Synthesis of Valuable Alcohols

Abstract

In the presence of PhSiH(3) as the reductant, the combination of enantiomeric dipyridylphosphane ligands and Cu(OAc)(2)·H(2)O, which is an easy-to-handle and inexpensive copper salt, led to a remarkably practical and versatile chiral catalyst system. The stereoselective formation of a selection of synthetically interesting β-, γ- or δ-halo alcohols bearing high degrees of enantiopurity (up to 99.9% enantiomeric excess (ee)) was realized with a substrate-to-ligand molar ratio (S/L) of up to 10,000. The present protocol also allowed the hydrosilylation of a diverse spectrum of alkyl aryl ketones with excellent enantioselectivities (up to 98% ee) and exceedingly high turn-over rates (up to 50,000 S/L molar ratio in 50 min reaction time) in air, under very mild conditions, which offers great opportunities for the preparation of various physiologically active targets. The synthetic utility of the chiral products obtained was highlighted by the efficient conversion of optically enriched β-halo alcohols into the corresponding styrene oxide, β-amino alcohol, and β-azido alcohol, respectively.

Synthesis and in Silico Evaluation of Novel Compounds for PET-Based Investigations of the Norepinephrine Transporter

“…Chloro-1-(4-fluorophenyl)propan-1-ol (9). Yield: 4.78 g (95%), pale yellow oil, analytical data are in complete accordance with literature values [38]. (10).…”

Selective Asymmetric Transfer Hydrogenation of α‐Substituted Acetophenones with Bifunctional Oxo‐Tethered Ruthenium(II) Catalysts

“…Regarding the derivatization of the obtained optically active haloalcohols, ( R )‐2‐chloro‐1‐phenylethan‐1‐ol 7 d was completely converted into the corresponding chiral ( R )‐epoxide 10 which is convertible to various important chiral compounds such as 2‐amino‐1‐alcohol,, β‐azido alcohol, and β‐methoxy alcohol (Scheme ).…”

Synthesis and Evaluation of Cyclic Sulfite Diesters as Sulfur Dioxide (SO2) Donors

“…The substituted phenacyl bromides were prepared by bromination of corresponding acetophenone. 7 Sodium borohydride (NaBH4) mediated reduction, followed by displacement of bromide under basic conditions 8 (1N NaOH) gave respective epoxides. To a solution of epoxide (0.500 g) in 10 mL 1,4-dioxane, 15 mL 10% aq.…”

“…15 Our laboratory has developed several strategies having different triggers for generating SO2 under physiological conditions using small organic molecules. [8] First, 2,4-dinitrophenylsulfonamides with tunable rates of generation of SO2 when triggered by biological thiols were reported (Scheme 1). The use of thiol is used as a trigger may complicate biological studies as targets of SO2 include biologically relevant disulfides and thiols.…”