Transition-metal-catalyzed regioselective aroyl- and trifluoro-acetylthiolation of alkynes using thioesters

Abstract

Intermolecular CO-retained carbothiolation of alkynes using thioesters took place to afford beta-SR substituted enone derivatives; the choice of catalyst (Pd(dba)(2)-dppe) and the introduction of a CF(3) group into the thioesters are the key to achieving the transformation.

Organometallic Approaches to Carbon–Sulfur Bond Formation

“…The use of thioesters represents the modern approach to carbothiolation. The reactivity of thioesters is similar to acid anhydrides, where the C-S bond can easily be activated by an appropriate low-valent transition metal [187,233,234]. Moreover, this approach circumvents the need for high pressures of carbon monoxide and is typically high yielding for the analogous carbonylated products.…”

“…The reaction proceeds in good-to-excellent yields and with high selectivity. In comparison, the use of a Pd(0) catalyst resulted in Equation 22 Use of thioesters in the analogous decarbonylative arylthiolation reaction [233] The products of standard hydrothiolation processes are capable of further undergoing subsequent transformations, such as Pt-catalyzed Heck reactions with appropriately tethered alkyne acceptors (23) [235]. Furthermore, Beletskaya demonstrated that following the organometallic intermediates formed in addition of disulfides to terminal alkynes may be intercepted; these were found to undergo further carboncarbon bond formation in the presence of a suitable ligand and excess alkyne (24) [158].…”

“…Use of thioesters as replacement for CO in Pd catalyzed carbothiolation [233] A Pt(0) complex was shown to catalyze decarbonylative arylthiolation of alkynes using thioesters (22). The reaction proceeds in good-to-excellent yields and with high selectivity.…”

“…A wide variety of sulfur derivatives can be used in these processes producing an array of interesting synthetic intermediates. These organosulfur compounds can be: free thiol [164, 167-170, 175, 190, 193, 197, 202, 204], disulfide [160,165,183,207], thiocyanate [179,182,186], thioborate [161], thiostannane [196], sulfenamide [180], and thioester [187,189,191,194,195]. Palladium catalyzed thiocarbonylation, and the development of multicomponent reactions centering on hydrothiolation with free thiols and disulfides has been reviewed extensively [19, 20, 23-26, 167, 227-231].…”

Preparation of α,β-unsaturated trifluoromethylketones and their application in the synthesis of heterocycles

“…Alternatively sulfides 42 can be prepared by the Pt-catalyzed regioselective trifluoroacetylthiolation of alkynes using thioesters 43. 24 Reaction of trifluoroacetimidoyl iodides 51 with various alkenes and alkynes in the presence of a palladium catalyst can be used for preparation of imino-derivatives of alkenyl 52 and alkynyl ketones 53. 28 Similarly, phosphonates 56 were prepared via reaction of diethyl allylphosphonate 55 with 54.…”