Synthesis of 2-perfluoroalkyl 4H- and 2H-chromenylphosphonates mediated by amines and phosphines.
An efficient synthesis of 2-perfluoroalkyl 4H-chromen-3-ylphosphonates 4a-i (R(F) = CF(3)) and 5a-i (R(F) = C(2)F(5)) has been accomplished via regioselective cycloaddition of 2-hydroxybenzaldehydes to diethyl 3,3,3-trifluoropropyn-1-yl- and diethyl 3,3,4,4,4-pentafluorobutyn-1-ylphosphonate, using trialkyl amines or phosphines as mediators. 2H-Chromen-3-ylphosphonates 6a-i were regioselectively obtained in the presence of triphenylphosphine. A convenient method for the isomerization of 4H-chromen-3-ylphosphonates into 2H-chromen-3-ylphosphonates 6a-i (R(F) = CF(3)) and 7a-i (R(F) = C(2)F(5)) was established.
School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany.
Blazej
B
Duda
Sergey N
SN
Tverdomed
Gerd-Volker
GV
Röschenthaler
D000447:Aldehydes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry*; D003500:Cyclization; D005466:Fluorocarbons / Q000138:chemical synthesis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010720:Phosphines / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D000588:Amines; D001578:Benzopyrans; D005466:Fluorocarbons; D010720:Phosphines; C013243:salicylaldehyde