Tridentate chiral NPN ligands based on bis(oxazolines) and their use in Pd-catalyzed enantioselective allylic substitution in molecular and ionic liquids

Abstract

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Naplephos through the Looking‐Glass: Chiral Bis(phosphanylamides) Based on β‐1,2‐D‐Glucodiamine and Their Application in Enantioselective Allylic Substitutions

“…In bmpyBF 4 , the first run quantitatively afforded the chiral product in high ee (94 %, Entry 8), which is the highest value reported so far2a,5a for this reaction under unconventional conditions. In subsequent recycles, the conversion was still complete (Entries 9 and 10), while the enantioselectivity only slightly decreased, as rarely observed13 in ionic solvents for AAA 14. The observed reduction of enantioselectivity and the simultaneous persistence of activity may be due to a gradual anomerization of the ligand, which is likely more sensitive at position 1.…”

Bis(oxazoline)-Based Coordination Polymers: A Recoverable System for Enantioselective Henry Reactions

“…The rest of purchased reagents were used as received without further purification. The ligands i -PrAzaBox-Me ( 4a ), − i -PrAzaBox-Bn ( 4b ), − i -PrBox-Bn ( 5b ), and i -PrDAX , were prepared according to literature procedures. The chemical shifts were relative to TMS as an internal reference for 1 H NMR.…”

Recent Applications of C 1-Symmetric Bis(oxazoline)-Containing Ligands in Asymmetric Catalysis

“…In 2011, Fraile and Mayoral tested C 1 -symmetric bis(oxazoline) ligands 110-113 ( Figure 18), which are based on phosphinooxazoline ligands, in asymmetric allylic substitution reactions (Scheme 38). 62 These ligands coordinate differently than the ligands already mentioned in this short review, binding to the metal center through one of the nitrogen atoms and the phosphorus atom rather than both nitrogen atoms. The level of enantiomeric excess that was obtained was in the order phosphite < phosphinite < phosphine.…”