3.2 L2 ligand Promoted Reaction
Duan et al. found that, using L2 as the ligand (entry 2 in
Scheme 2), the reaction did not proceed at all and no product was
obtained. To understand this interesting observation, we firstly
investigated the relative stabilities of various adducts formed by the
coordination of L2 ligand with Pd(OAc)2 shown
in Scheme 5, and examined two sequential processes involving
C(sp2)-H bond cleavage of aromatic ring through CMD
process and alkyne insertion from the starting materials
(L2+Pd(OAc)2 )(Figure 4).