Reaction of Alkynes

Abstract

Since the earliest investigations represented by cycloaddition [1] and carboxylation [2], the nickel-catalyzed reactions of alkynes have been extensively studied by many research groups. This chapter highlights recent developments in the nickelcatalyzed reactions of alkynes. Recent advancements in cycloaddition and the carboxylation of alkynes are described in Chapters 6 and 7, respectively.The most extensively studied reaction is the addition reaction of an AaB species (e.g., HaH, H-metals, metals-metals, CaH, and C-metals, where metals ¼ Si, Sn, B, etc.) to alkynes (Scheme 4.1). Generally, the addition of an AaB species to alkynes starts with oxidative addition of the AaB species to a nickel(0) complex to generate an AaNiaB species (see Section 1.7.1). The insertion of an alkyne into either the AaNi or the BaNi bond gives the alkenylnickel intermediate(s), which undergo reductive elimination to produce the alkenes functionalized with an A and B functionalities at the 1,2-positions (see Section 1.7.4). The A and B groups are usually introduced on the same face of alkynes, and cis-alkenes with respect to A and B are produced. When an AaB is CaX (X ¼ halogens, O, N), the alkenylnickel X intermediates are capable of undergoing, instead of reductive elimination, Modern Organonickel Chemistry. Edited by Y. Tamaru

Nickel-Catalyzed trans-Alkynylboration of Alkynes via Activation of a Boron−Chlorine Bond

“…In this paper, we describe another example of carboboration of alkynes. The reaction proceeds through the activation of the boron−chlorine bond by a nickel catalyst, , followed by delivery of an organic group from organostannanes, affording formal trans -carboboration products.…”

Enantioselective Metal-Catalyzed Reductive Coupling of Alkynes with Carbonyl Compounds and Imines: Convergent Construction of Allylic Alcohols and Amines

“…Corresponding enantioselective reductive cyclizations of acetylenic carbonyl compounds and imines are not covered. , The discussion is limited to processes that result in C–H and C–C bond formation via formal addition of H 2 across the alkyne pronucleophile and CX (X = O, NR) π-bond. Hence, multicomponent intermolecular alkylative ,, alkyne-CX (X = O, NR) reductive couplings are not covered (nor are related alkylative/arylative or borylative/silylative cyclization processes). Finally, metal-catalyzed reductive couplings of alkynes with carbon dioxide are beyond the scope of this review .…”