Ruthenium‐catalyzedcycloisomerization of 2‐ethynylbiaryls was investigated to identify an optimal ruthenium catalyst system. A combination of [η6‐(p‐cymene)RuCl2(PR3)] and two equivalents of AgPF6 effectively converted 2‐ethynylbiphenyls into phenanthrenes in chlorobenzene at 120 °C over 20 h. Moreover, 2‐ethynylheterobiaryls were found to be favorable substrates for this ruthenium catalysis, thus
Reported here is the direct synthesis of naphthofurans and benzofurans from readily available phenols and α-haloketones promoted by titanium tetrachloride which combines Friedel–Crafts-like alkylation and intramolecular cyclodehydration into one step. This simple protocol allows for the formation of a variety of high value naphthofurans and benzofurans within which a series of cyclic and acyclic groups
Studies on the Chemical Constituents of Rutaceous Plants. Part LXIX. Cesium Fluoride-Mediated Claisen Rearrangement of Aryl Propargyl Ether. Exclusive Formation of 2-Methylarylfuran and Its Availability as a Masked Salicylaldehyde.
Claisen rearrangement of an aryl propargyl ether in the presence of CsF led to exclusive formation of 2-methylarylfuran in excellent yield. The result of a precise examination of the rearrangement is described. Satisfactory transformation of the 2-methylarylfuran to a salicylaldehyde derivative was achieved by stepwise oxidation. This combination of reactions serves as a useful method for regioselective introduction of a C1 unit at the ortho position of a phenol group.