Development of π-acidic metal-catalyzed reactions toward construction of multi-substituted heterocycles

π-Acidic metal-catalyzed cyclization reaction is one of the most efficient methods to construct highly elaborate molecular skeletons in a single operation under mild reaction conditions. These transformations often involve cleavage of σ bonds. Investigations into catalytic skeletal rearrangement have mainly utilized alkynylamines, alkynylalcohols, enynes, and propargylic esters as substrates. In this article, I report our recent findings on π-acidic metal catalyzed reactions via cleavage of σ bonds between major elements in body, such as carbon, nitrogen, oxygen, and sulfur, producing multisubstituted heterocycles in an atom efficient manner. That is, (a) catalytic carbon-heteroatom bond addition of ortho-alkynylphenyl ethers, -anilines, and -phenyl sulildes and (b) catalytic skeletal rearrangement of propargylic oximes.