Intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes leading to spiro[4,5]trienones: scope, application, and mechanistic investigations.

A new, general method for the synthesis of spiro[4,5]trienones is described by the intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes. In the presence of halide electrophiles, a variety of 4-(p-unsubstituted-aryl)-1-alkynes underwent the intramolecular ipso-halocyclization with water smoothly, affording the corresponding halo-substituted spiro[4,5]trienones in moderate to good yields. The obtained spiro[4,5]trienones can be applied in constructing the azaquaternary tricyclic skeleton via Pd-catalyzed Heck reaction.

Selective synthesis of 3-aryl quinolin-2(1H)-ones and 3-(1-arylmethylene)oxindoles involving a 2-fold arene C-H activation process.

A novel and selective palladium-catalyzed C-H activation protocol has been developed for the synthesis of 3-aryl quinolin-2(1H)-ones and 3-(1-arylmethylene)oxindoles with use of PivOH as the switch. In the presence of Pd(OAc)(2), AgOAc, and PivOH, a variety of N-methyl anilides reacted with arenes to afford the corresponding 3-aryl quinolin-2(1H)-ones in moderate yields, whereas the selectivity was shifted toward 3-(1-arylmethylene)oxindoles in the absence of PivOH.

Selective synthesis of spiro[4,5]trienyl acetates via an intramolecular electrophilic ipso-iodocyclization process.

A general and efficient intramolecular electrophilic ipso-iodocyclization of para-unactivated arylalkynes has been developed for the synthesis of spiro[4,5]trienyl acetates. In the presence of NIS (N-iodosuccimide) and HOAc, para-unactivated arylalkynes, including N-arylpropiolamides and phenyl 3-phenylpropiolate, underwent the intramolecular electrophilic ipso-iodocyclization smoothly in moderate to good yields.