Addition of secondary phosphines to phenylcyanoacetylene as a route to functional phosphines

Noncatalytic Regio- and Stereoselective Addition of Secondary Phosphines to Cyanoacetylenic Alcohols

“…The doublet ethenyl proton signals in the range 6.236.5 ppm ( 3 J HP 5.4 and 6.6 Hz), observed in the 1 H NMR spectra of phosphines IIb and IIc, should, according to published data [3,5,10,11], correspond to cis location of hydrogen and phosphorus. However, the presence in the two-dimensional 1 H3 1 H NOESY NMR spectra of these phosphines of cross peaks corresponding to interaction of protons of the ethenyl and methyl groups, that is only possible if these groups are cis to each other, provides unambiguous evidence for Z configuration of compounds IIb and IIc.…”

“…In the case of the less sterically congested dimethylphosphine, a mixture of (Z)-and (E)-3-(dimethylphosphino)acrylonitriles (1 : 2) is formed in 50% yield [3]. The chemo-, regio-, and stereoselective addition of primary [4] and secondary [5] phosphines to phenylcyanoacetylene has been reported, leading to corresponding secondary and tertiary cyanoethenylphosphines of Z configuration in an almost quantitative yield. Furthermore, a short communication on the reaction of 4-hydroxy-4-methyl-2-pentynenitrile with secondary phosphines has been published [4].…”

“…8 Hz), which is more characteristic of the E isomers of such compounds [3,5,10,11]. The 1 H3 1 H NOESY NMR spectrum of phosphine IIa does not give such an unambiguous picture as the spectra of compounds IIb and IIc, because the signal of the methyl group is overlapped by the multiplet of methylene protons of the butyl substituent.…”

The Phospha‐Michael Addition in Organic Synthesis

“…More recently, Arbuzova and co-workers [94] undertook the phosphorylation of other cyanoacetylenes. Preferential formation of the Z isomer was also observed and explained with the trans-mode of nucleophilic addition to activated acetylenes [95] as well as for steric reasons (Scheme 50).…”

Nucleophilic and free-radical additions of phosphines and phosphine chalcogenides to alkenes and alkynes

“…140,141,151 Thus, reaction of 2,6-bis(trifluoromethyl)phenyl]phosphine with phenylacetylene (100-110°C, 40 h) gave E-and Z-isomers of secondary [2,6- Dialkylphosphines react with cyanoacetylene to afford exclusively or predominantly Z-isomers of the corresponding alkenes Alk 2 PCH=CHCN. 146 The reaction of bis(2-phenylethyl)-and bis(2-phenylpropyl)phoshines (1a,i) with phenylcyanoacetylene proceeds with the same stereodirection to give mainly monoadducts 31a,b, 157 though in the case of 1i a considerable amount of E-isomer 32b is formed (Scheme 20) that is explained by the competition of trans-and cis-addition to triple bond owing to steric hindrance. According to ESR and UV data, the reaction involves a single electron transfer.…”