(The) study on the synthesis & applications of vinyl or allyl phosphorus derivatives

Abstract

The reaction of organocopper (Ⅰ) reagents with 1-alkynylphosphonates affords a rapid entry into a variety of vinylic phosphonates with regio- and stereospecific isomers and high yields in a one-pot process. 1-Alkynyl phosphonates are easily converted into 1-phosphonyl-2,2-dialkyl vinylcopper (Ⅰ) intermediates by treatment with organocopper (Ⅰ) reagents. The intermediates react with a variety of electrophiles to give the vinyl phosphonates derivatives RR``C=$C(E)PO_3Et_2$ (E= H, I, Me, allyl, SePh, TePh, $SiMe_3$). The stereochemistry of the carbocupration of 1-alkynyl phosphonates with organocopper (Ⅰ) reagents is observed to occur with syn-addition (R= H, n-Bu, n-Hex, $CH_2OBn$, Ph) and unexpected anti- addition in the case of R= t-Bu. The β-keto-ω-alkenyl phosphonates affords the mono- and spirocyclic α-phosphonato-α,β-unsaturated cycloenones (β``-ketovinyl phosphonates) via ozonolysis-aldol sequence with the aid of p-TsOH and $Et_3N$ as catalysts. Lithiated alkylphosphonates are allylated with allyl bromide and undergo epoxidation with MCPBA, to give γ,δ-epoxyalkylphosphonates, which are dissolved in THF and treated with n-BuLi at -78℃ to afford the hydroxymethyl-cyclopropylphosphonates via epoxide opening. The 1-formylalkanephosphonates are obtained by the ozonolysis of the corresponding 1-alkylated allylphosphonates, which have been previously prepared by treatment with n-BuLi, followed by addition of alkyl halides. The allylphosphites with MgBrCl without the solvent are rearranged to the allylphosphonates. The allylphosphites undergo a stereoselective and regioselective rearrangement to the allylphosphonates containing Ph, p-ClPh, p-MeOPh, 2-furan, 3-thiophene at 3-position of phosphonates and the configuration of olefin is only E-form. However the rearrangements of allylphosphites containing $p-(Me)_2NPh$, 1-hexene give mixtures.