Copper(ii)-catalyzed direct dehydrative alkynylation of 2H-chromene hemiketals with terminal alkynes to 2,2-disubstituted 2-alkynylated 2H-chromenes

Abstract

The first copper-catalyzed direct dehydrative alkynylation of 2H-chromene hemiketals with terminal alkynes has been uncovered. The use of cheap and readily available CuCl2 as catalyst allowed the preparation of various...

Dehydrative alkynylation of 3-hydroxyisoindolinones with terminal alkynes for the synthesis of 3-alkynylated 3,3-disubstituted isoindolinones

“…1 Consequently, extensive efforts have been devoted to the development of efficient methods for the construction of organic molecules bearing C(sp)–C(sp 2 ) bonds or C(sp)–C(sp 3 ) bonds. 2 Among strategies for C(sp)–C(sp 3 ) bond formation, 2 e ,3–7 the alkynylation of electrophilic cationic N , O -acetals such as N -acyliminium ions represents one of the key reactions in forming propargylic amines. 2 e ,5 b ,8 However, in these reactions, there are only two examples using readily available terminal alkynes as alkynylation reagents (Scheme 1a).…”

“…Following our continued research interest in the dehydrative cross-coupling reactions of alcohols 14 to construct heterocycles 15 and alkyne-related chemistry, 16 and also considering the potential uses of 3-alkynylated 3,3-disubstituted isoindolinones in medicinal research, we conceived that employing terminal alkynes as nucleophiles to react with 3-hydroxyisoindolinones might fulfill the task of synthesizing 3-alkynylated 3,3-disubstituted isoindolinones. The success of this reaction would not only expand the chemical space of isoindolinones comprising a quaternary carbon centre, but also add a new dimension to the existing methods for the synthesis of 3-alkynylated 3,3-disubstituted isoindolinones.…”