Trisubstituted alkenylmetals cross-coupling

Some representative examples of the cross-coupling of three different types of trisubstituted alkenylmetals with aryl electrophiles are shown in Table 6 and arranged in the order /3,/3 -, cis-a, -, and lra i-Q ,j8-substituted alkenylmetals. 

TABLE 6. Pd-Catalyzed Cross-Coupling of Trisubstituted Alkenylmetals with Aryl Electrophiles ... 

Haloboration of 1-aIkynes followed by chemoselective cross-coupling can provide j8,/3-substituted alkenylborons that undergo Pd-catalyzed coupling with alkenyl halides to give stereodeflned trisubstituted alkenes. The use of other /3,/3-substituted alkenyl-metals has also been demonstrated. For example, exocyclic alkenylmetals containing Zn and Sn have been nsed in Pd-catalyzed cross-coupling approach to the vitamin D skeleton as shown in Scheme 65. It shonld be noted that the alkenylzinc appeared to be distinctly snperior to the corresponding alkenyltins. 

---

See also in sourсe #XX -- [ , , , , ]

---