Catalytic Markovnikov and anti‐Markovnikov Functionalization of Alkenes and Alkynes: Recent Developments and Trends

Abstract

The regioselective functionalization of terminal alkenes and alkynes is of utmost importance for the synthesis of a wide variety of organic products. Based on the original observation by Vladimir Markovnikov-the pioneer of this field of research-in the 19th century, the possible regioisomeric products are classified as Markovnikov or anti-Markovnikov products. Contrary to traditional belief, it is nowadays possible to control the regiochemistry of various additions of nucleophiles to alkenes and alkynes by applying different transition-metal catalysts. Recent developments in this area of selective functionalization of alkenes and alkynes are reviewed.

Reactions of Titanocene- and Zirconocene-Bis(trimethylsilyl)acetylene Complexes with Selected Heterocyclic and Aromatic NH and OH Acid Compounds

“…Related hydroamination processes were reported with catalysts such as CpTiCl 3 23 and the titanocene-alkyne complex Cp 2 Ti(η 2 -Me 3 SiC 2 SiMe 3 ) (1) used by Beller et al 24 .…”

Ruthenium-catalyzed intermolecular [2+2+2] alkyne cyclotrimerization in aqueous media under microwave irradiation

“…Both aromatic (2cÁf) and aliphatic (2gÁk) terminal alkynes, as well as the acetylenic esters 2lÁm or the keto-alkyne 2n, could be smoothly cyclotrimerized within 1 h, the reactions delivering the corresponding arenes in 71Á92% isolated yield after silica-gel chromatography. However, we must note that in a few cases (entries 8, 12, 16, and 18) formation of minor amounts of methylketones as by-products was observed, as the result of a competing Ru-catalyzed Markovnikov hydration of the alkyne (54,55). Such a side reaction does not Conditions A: conventional oil-bath heating at 758C.…”

Ruthenium piano-stool complexes bearing imidazole-based PN ligands

“…6,7,8,9,10,11,12,13 Besides these homogenous catalysts also heterogenous catalyst systems are used. 14,15,16 The first ruthenium(II) complex to be known to catalyze the anti-Markovnikov hydration was a phosphine complex described by Tokunaga and Wakatsuki. 17,18 The catalytic activity as well as the selectivity of ruthenium(II) depends on the nature of the phosphine ligands.…”