Highly diastereoselective vinylogous Mukaiyama aldol reaction of alpha-keto phosphonates with 2-(trimethylsilyloxy)furan catalyzed by Cu(OTf)(2)

The diastereospecific formation of delta-hydroxyalkylbutenolide phosphonate has been achieved via a vinylogous Mukaiyama aldol reaction. The reaction was performed using alpha-ketophosphonate 1 and 2-(trimethylsilyloxy)furan 2 mediated by Cu(OTf)(2) and 2,2,2-trifluoroethanol as additive in CH2Cl2. The reaction proceeds rapidly and affords the corresponding 5-(hydroxy(aryl)methyl)furan-2(5H)-one phosphonates 3 in high yields with good to excellent diastereoselectivities (d.r. up to > 99 : 1). 5-(Hydroxy(alkyl)methyl)furan-2(5H)-one phosphonates could also be obtained with good diastereoselectivities.