A New Class of Modular Phosphinite–Oxazoline Ligands: Ir-Catalyzed Enantioselective Hydrogenation of Alkenes We thank Dr. Martin Studer and Dr. Benoît Pugin (Solvias AG, Basel) for fruitful discussions, and Prof. Kevin Burgess (Texas A&M University) for preprints of related unpublished work. Financial support by the Swiss National Science Foundation is gratefully acknowledged.

Abstract

Both enantiomers are readily prepared of phosphinite–oxazoline ligands 1 from the D and L enantiomers of serine (see Scheme). Iridium complexes derived from these ligands (the structure of one complex is shown) are excellent catalysts for the enantioselective hydrogenation of unfunctionalized alkenes. R1=ferrocenyl, aryl; R2=alkyl, benzyl.

Enantioselective Hydrogenation of Unfunctionalized Alkenes

“…30.10) hydrogenated substrates 36 and 38-40 in good yield and ee [19], significant progress was made with the second generation of catalysts [22]. While the first generation of these catalysts (SerPHOX 46, Fig.…”

P,N and Non‐Phosphorus Ligands

“…More recent developments are the SerPHOX catalyst 22 [20] and the Thre-PHOX catalyst 23 [21] (Fig. 29.9), derived from serine or threonine, respectively (Scheme 29.4).…”

New chiral N,P-oxazolines, and their Ir complexes in asymmetric hydrogenation of an imine

“…Most such ligands (that coordinate, for example, via N,N- [6][7][8][9], N,O- [10,11], N,P- [2,3,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30], N,S- [7,27,[31][32][33], N,C- [34,35], N,N,N- [2,9,36], N,O,N- [36][37][38], N,P,N- [2], N,S,N- [37,39], N,N,O,N,N- [37,38], N,N,N,N- [37,38], and N,N,N,N,N,N-bonding modes [37,38]) have their second (and other) heteroatom tethered to the oxazoline ring through the 2-position (see …”