Calcium-Mediated Catalytic Synthesis of 1-(Diorganylamino)-1,4-diphenyl-4-(diphenylphosphanyl)buta-1,3-dienes

摘要

The hydroamination of diphenylbutadiyne with 1 equiv of the secondary amines HNRR' (R/R' = Ph/Ph, Ph/Me, and pTol/Me) in the presence of catalytic amounts of the tetrakis(amino)calciate K-2[Ca{N(H)Dipp}(4)] (Dipp = 2,6-diisopropylphenyl) yields the corresponding 1-(diorganylamino)-1,4-diphenylbut-1-ene-3-ynes as a mixture of E/Z isomers. These tertiary alkenylamines react with diphenylphosphane to form RR'N-C(Ph)-CH-CH-C(Ph-PPh2 [R/R' = Ph/Ph (1), Ph/Me (2), and pTol/Me (3)] in the presence of catalytic amounts of [(THF)(4)Ca(PPh2)(2)] or of the same calciate K-2[Ca{N(H)Dipp}(4)]. Whereas the hydroamination is regio- (amino group in 1-position) but not stereoselective (formation of E and Z isomers), this second hydrofunctionalization step is regio- (phosphanyl group in 4-position) and stereoselective (only E isomers are formed), finally leading to mixtures of (E,E)- and (Z,E)-1-(diorganylamino)-1,4-diphenyl-4-(diphenylphosphanyl)buta-1,3-dienes.