Platinum‐Catalyzed Regioselective Formation of β‐Alkoxy Ketones from Internal Alkynes

Abstract

A catalytic amount of Zeise's dimer and 15-crown-5 were combined to effectively promote the regioselective formation of β-alkoxy ketones from 2-(homopropargyloxy)ethanols in dimethoxyethane. The desired products were obtained in 59-

Chemoselectivities in the Platinum-Catalyzed Hydrative Carbocyclizations of Oxo-Alkyne-Nitrile Functionalities

“…Regiocontrolled metal-catalyzed hydrations of alkynes to form carbonyl derivatives are of prime interest in organic synthesis. , Hydrative coupling of an alkyne with another functionality is particularly interesting because it not only introduces a carbonyl group but also allows formation of a C−C bond. Metal-catalyzed three-component couplings are powerful tools to access complicated frameworks, but hydrative carbocyclizations of alkynes are exclusively focused on two-component coupling reactions, including 1, n -diynes, 1-yne-5-enones, 1-en-5-ynes, and 1-allen- n -ynes ( n = 5−7), with rare examples for three-component coupling reactions .…”

Mechanistic Dichotomy with Alkynes in the Formal Hydrohydrazination/Fischer Indolization Tandem Reaction Catalyzed by a Ph3PAuNTf2/pTSA Binary System

“…Under these conditions, 3p and 3q were obtained in 86 and 83 % yields, respectively. However, it is also possible that, in the presence of hydrated p TSA, 6a and 6b may open up to form the corresponding ketones, and it may be these ring‐opened species that are the actual reaction partners 23. It was also found that the reaction proceeded well under anhydrous conditions; see Equations (5) and (6) below.…”

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

“…Despite this, in 2010, Liu reported the platinum-catalyzed regioselective α-hydration of homopropargylic ethers 49 in DME (Scheme 32). 69 After investigating a variety of metal catalysts such as AuCl, Au(PPh 3 )Cl/AgOTf, Hg(OTf) 2 , PtCl 2 , and others, the authors showed that Pt 2 Cl 4 (C 2 H 4 ) 2 (Zeise's dimer 51) gave the best αregioselectivity on a model substrate (80/20). Then, they added various Pt ligands to increase the α/β ratio.…”