Synthesis of Phosphanyl Sulfoximines Through Phospha‐Michael Reaction of Alkenyl Sulfoximines and Their Evaluation as Chiral Bidentate 1,5‐N,P Ligands for Palladium in Asymmetric Allylic Alkylation

Abstract

The intermolecular phospha-Michael reaction of cyclic and acyclic alkenyl sulfoximines proceeds readily and yields the corresponding phosphanyl sulfoximines in good yield. The asymmetric induction provided by sulfoximine group in C-P bond formation is apparently only low. The configuration of three phosphanyl sulfoximine-boranes has been determined by X-ray crystal structure analysis. The ability of the phosphanyl sulfoximines to act as ligand in Pd-catalyzed asymmetric allylic alkylation was studied with pairs of diastereomeric cyclic and acyclic derivatives carrying different substituents at the N atom. This study showed that the substituent at the N atom and both the chirality of the backbone and sulfoximine group play a crucial role in determining the enantioselectivity of the allylic alkylation. The Pd-catalyzed reaction of the racemic 1,3-diphenylallyl acetate with the mal-

Chiral Organosulfur Ligands/Catalysts with a Stereogenic Sulfur Atom: Applications in Asymmetric Synthesis

“…The cyclic phosphanyl sulfoximines 209 proved to be very efficient ligands and gave products 72 in up to 98% yield and with up to 97% ee. On the contrary, the acyclic analogues 208 gave worse results. , …”

“…On the contrary, the acyclic analogues 208 gave worse results. 121,122 N-Phosphorylated sulfoximines, containing diazaphospholidine 210a,b or oxazaphospholidine 211a,b ring (Figure 63), bearing three stereogenic centers, and having absolute configurations as shown below, were used as ligands in various enantioselective palladium-catalyzed allylic substitutions (Scheme 55). In the case of the allylic aminations of 71 with pyrrolidine as the N-nucleophile, compounds 210 afforded product 212 in almost quantitative yields and with very good enantioselectivities (79−90% ee), regardless of the solvent or the ligand-to-metal ratio.…”

Sulfoximine‐Directed Single and Double ortho‐Lithiation: Stereoselective Rearrangements of o,o′‐Dilithiophenylsulfoximines to o,N‐Dilithiosulfinylanilines through Anionic Fries Rearrangements of o,o′‐Dilithiophenylsulfinamides

“…[3] Because of the envisioned investigation of double ortho-lithiations of acyclic and cyclic sulfoximines (see below) and our interest in the synthesis of phosphanyl sulfoximines as chiral ligands, [28] …”

Sulfur‐Bearing Lithium Compounds in Modern Synthesis

“…In 2000, Gais and coworkers [104] reported the diastereoselective synthesis of chiral β,βdisubstituted-β-amino acids by the double lithiation of α-sulfoximines (previously prepared by the same group [105]) followed by capture with methyl chloroformiate and final rupture of the C-S bond with Ni-Raney (Scheme 8.27). More recently, Gais and coworkers [106] have described the synthesis of phosphanyl sulfoximines and their use as chiral bidentate 1,5-N,P ligands for palladium asymmetric allylic alkylation. More recently, Gais and coworkers [106] have described the synthesis of phosphanyl sulfoximines and their use as chiral bidentate 1,5-N,P ligands for palladium asymmetric allylic alkylation.…”