Highly enantioselective conjugate additions of phosphites to alpha,beta-unsaturated N-acylpyrroles and imines: a practical approach to enantiomerically enriched amino phosphonates.
The first highly enantioselective phosphonylation of alpha,beta-unsaturated N-acylpyrroles has been developed. Excellent yields (91-99 %) and enantioselectivities (up to >99 % enantiomeric excess (ee)) were observed for a broad spectrum of both phosphites and N-acylpyrroles under mild conditions. In particular, when diethyl phosphite was employed to test the scope of the N-acylpyrroles, almost optically pure products (98 to >99 % ee) were obtained for 20 examples of N-acylpyrroles. Moreover, optically pure alpha-substituted beta- or gamma-amino phosphonates can be obtained by several simple transformations of the pyrrolyl phosphonates. The versatility of the N-acylpyrrole moiety makes the phosphorus adducts powerful chiral building blocks that enable the synthesis of various phosphonate-containing compounds. Finally, the present strategy can also be applied to the asymmetric hydrophosphonylation of N-acylimines with high enantioselectivities (93 to >99 % ee).
Zhao
Depeng
D
State Key Laboratory of Applied Organic Chemistry and Institute of Biochemistry and Molecular Biology School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Wang
Yuan
Y
Mao
Lijuan
L
Wang
Rui
R
D000588:Amines / Q000737:chemistry; D002384:Catalysis; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D063065:Organophosphonates / Q000138:chemical synthesis* / Q000737:chemistry; D017905:Phosphites / Q000737:chemistry*; D011758:Pyrroles / Q000737:chemistry*; D013237:Stereoisomerism
D000588:Amines; D007097:Imines; D063065:Organophosphonates; D017905:Phosphites; D011758:Pyrroles