Palladium‐Catalyzed Enantioselective C−H Olefination of Diaryl Sulfoxides through Parallel Kinetic Resolution and Desymmetrization

Abstract

The first example of Pd -catalyzed enantioselective C-H olefination with non-chiral or racemic sulfoxides as directing groups was developed. A variety of chiral diaryl sulfoxides were synthesized with high enantioselectivity (up to 99 %) through both desymmetrization and parallel kinetic resolution (PKR). This is the first report of Pd -catalyzed enantioselective C(sp )-H functionalization through PKR, and it represents a novel strategy to construct sulfur chiral centers.

Mild and Regioselective Bromination of Phenols with TMSBr

“…A 5 mmol scale reaction of 1a and 2a could afford the target product 4a in 85 % yield (0.735 g, > 95 % purity) only by simple filtration and extraction . Meanwhile, the by‐product 6f could be easily recycled in > 95 % yield, followed by readily oxidized to sulfoxide 3f , thus entering into the next reaction cycle (Equation 1)…”

Lewis acid-assisted Ir(iii) reductive elimination enables construction of seven-membered-ring sulfoxides

“…In addition, Cp*RhCl 2 , (p-cymene)RuCl 2 and Pd(OAc) 2 catalysts were also tested in the reaction, as these catalytic systems usually display high reactivity in some sulfoxide directed C-H functionalization reactions. [45][46][47][48][49][50][51][52][53] However, for this typical transformation, no yield of 2a could be obtained (see the ESI Table S6 † for details).…”

Enantioselective Synthesis of Chiral‐at‐Sulfur 1,2‐Benzothiazines by CpxRhIII‐Catalyzed C−H Functionalization of Sulfoximines

“…Examples of using this concept to create stereogenic phosphorus or silicon atoms are more scarce. Related methods to access chiral sulfur atoms are, to the best of our knowledge, elusive, except for a single example for chiral sulfoxides reported by Wang and co‐workers . On the basis of our findings of creating P‐chirality with chiral cyclopentadienyl (Cp x ) rhodium and iridium catalysts,,, we explored the suitability of these for the generation of sulfoximines with chiral sulfur atoms.…”