Cobalt‐Catalyzed Hydroalkynylation of Vinylaziridines

Abstract

Transition metal-catalyzed hydroalkynylation reactions are efficient transformations allowing the straightforward formation of functionalized alkynes. Therein, we disclose the cobalt-catalyzed hydroalkynylation of vinylaziridines giving rise to both linear and branched enynes. The optimization of the reaction conditions allowed to determine the key parameters of the cobalt-based catalytic system. The scope investigation showed that the cobalt-catalyzed hydroalkynylation is mainly limited to phenylacetylene derivatives. In most cases branched and linear enynes were isolated in equimolar proportions (20 examples). Additional experiments allowed us to propose a plausible mechanism. Finally, the hydroalkynylation products were further subjected to an iodocyclization affording a 2,3-dihydropyrrole derivative and a platinum-catalyzed cycloisomerization.

Cobalt-Catalyzed Alkynylation of Organic Compounds: Hydroalkynylation, Dehydrogenative Alkynylation, and Reductive Alkynylation

“…In this reaction, the addition of the alkynyl moiety to the C=C bond of vinylaziridines and subsequent ring-opening of the threemembered ring afforded branched and linear enynes 28 and 29 in an approximately 1:1 ratio (eq 16). 23 Equation 16 Alkynylation and ring-opening of vinylaziridines…”

Copper Nitrate Mediated Regioselective Difunctionalization of Alkenes with N-Fluorobenzenesulfonimide: A Direct Approach to β-Aminonitrates

“…In the presence of magnesium chips, acetic acid, and sodium acetate, β-hydroxysulfonamide 4 was obtained in 70% yield. β-Hydroxysulfonamide is a versatile synthon, which could be transformed into aziridine, 21 monofluoroalkene-masked heterocyclic lactones, 22 and substituted morpholines. 23 Treatment of 2a with KOH in EtOH gave N -(2-ethoxy-2-( p -tolyl)ethyl)benzenesulfonamide ( 5 ) in 63% yield accompanied by the formation of 6 in 27% yield, in which an aziridine intermediate was involved.…”

Cobalt‐Catalyzed Cascade Reaction of Ynamides and 1,3‐Dicarbonyl Compounds for Selective Synthesis of Differently SizedN‐Heterocycles

“…In contrast, less attention has been paid to the analogous cascade cyclization reaction. The development of costefficient earth-abundant metals for practical applications, especially catalysts that are based on first-row transition metals (such as Co [8] ) for cascade cyclization reaction is highly desirable. [9] However, selective synthesis of differently sized N-heterocycles via non-noble metal catalyzed cascade cyclization is a challenge, mainly due to the poor reactivity of non-noble metals during cyclization.…”