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Highly Efficient Asymmetric Conjugate Hydrocyanation of Aromatic Enones by an Anionic Chiral Phosphate Catalyst
Author(s) -
Wang YaoFeng,
Zeng Wei,
Sohail Muhammad,
Guo Jiyi,
Wu Shaoxiang,
Chen FuXue
Publication year - 2013
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201300406
Subject(s) - chemistry , hydrocyanation , catalysis , cyanohydrin , enantioselective synthesis , benzophenone , nitrile , conjugate , chalcone , nucleophile , organic chemistry , nucleophilic substitution , substrate (aquarium) , combinatorial chemistry , mathematical analysis , oceanography , mathematics , geology
Chiral keto nitriles (β‐cyano ketones) have been prepared by a facile and efficient asymmetric conjugate hydrocyanation of poorly active chalcone‐type enones with benzophenone cyanohydrin. Using in situ generated 5–10 mol‐% of sodium ( S )‐6,6′‐di(1‐adamantyl)‐1,1′‐binaphthyl‐2,2′‐diyl phosphate as catalyst and 5–10 mol‐% of 2‐ tert ‐butylphenol as an additive, high yields and excellent enantioselectivities were obtained within 2 h in toluene at 80 °C. The development of catalysts, optimization of the reaction parameters, and substrate scope are reported. On the basis of the experimental results, HCN is shown to be the real cyanide source and a mechanism is proposed to explain the origin of the enantioselectivity with the chiral‐anion‐modified nucleophile HCN.