With the optimized reaction conditions in hand, the scope of unactivated alkynes was examined (Fig ). The reaction has broad functional group compatibility and a plethora of aliphatic alkynes proved to be suitable substrates, delivering synthetically useful yields with good stereoselectivity. The preparation of 3a could be scaled up, giving a slightly decreased but acceptable yield. A diversity of susceptible groups, such as an unprotected alcohol (3e), iodide (3f), azide (3j), carboxylic acid (3l, 3m) or silane (3n), remained intact in the reaction. Notably, acetylene gas was also suitable for this reaction to afford the corresponding E-allylic alcohol (3o). A cyanoamide (3q) that could act as radical acceptor via 5-exo-dig cyclization did not interfere with the desired difunctionalization 35-36 . Though phenylsulfonyl 37-40 alkenylsulfonyl 41-42 and malonitrile 43-45 moieties all possess some migratory aptitude, the competitive migration of those groups did not occur in the cases of 3s-3v, indicating that the migration of the benzothiazolyl group was faster. The reaction proceeded selectively at a terminal alkyne in the presence of an additional internal alkyne (3x). Alkyl carboxylate, phosphonate or sulfonate esters as substrates afforded the corresponding products (3y-3ab) with comparable yields. Substrates containing various heterocyclic fragments including piperidyl (3ac), benzofuryl (3ad), thienyl (3ae), quinolyl (3af), quinoxalinol (3ag), or isatoic anhydride (3ah) were also compatible with the reaction conditions. The E-configuration of the alkene in the product was unambiguously confirmed by the crystal structure of 3ai (see SI). Using alcohols or aromatic amines as a nucleophilic solvent instead of water resulted in the corresponding allylic ethers (3aj, 3ak) or allylic amines (3al-3an). Remarkably, the method could be used to synthesize valuable cyclic compounds in one step. For instance, the reaction of alkynols under the current conditions led to 2H-pyran (3ao) or oxepene (3ap) by intramolecular cyclization. Moreover, the reaction of alkynoic acids gave rise to δ-pentenolide (3aq) and εcaprolactone (3ar), following a reaction in which the carboxylic acid served as a nucleophile. In addition to electron-rich aliphatic alkynes, electron-deficient propionic acid was also amenable to the reaction, albeit with a lower yield. The conversion afforded the decarboxylative product (3o), the formal difunctionalization of acetylene.