Markovnikoff adducts

Addition of the P—H bond of hydrogen phosphonates (R0)2P(0)H across alkynes (hydrophosphorylation) may be catalyzed using both Pd° and Pd11 complexes.196 Reaction of oct-l-yne with either (MeO)2P(0)H or (EtO)2P(0)H affords the Markovnikoff adduct (Equation (18)) as the... 

The reaction of 231 with styrene was catalyzed by boron trifluoride to give the Markovnikoff adduct 232 (equation 113), while the addition of 231 to cyclohexene gave solely the trans adduct 233. The uncatalyzed reaction with styrene afforded the anti-Markovnikoff adduct 234 (equation 114). The reaction of selenolsulfonates with acetylenes proceeds in refluxing benzene or chloroform without boron trifluoride ethe-rate103 104, and produces only a single adduct 237 in a stereo- and regioselective fashion (equation 115). The addition of selenolsulfonates to acetylenes is shown in Table 10. When... 

Markovnikoff adduct (76), although the two products are interconverted on heating (see also Chapter 4, p. 193). 

---