A Ligand Free and Room Temperature Protocol for Pd-Catalyzed Kumada−Corriu Couplings of Unactivated Alkenyl Phosphates

Cross‐coupling reaction of organogold(I) phosphanes with organic electrophiles in aqueous media has been investigated. Reactions between isolated aryl‐, alkenyl‐, or alkynylgold(I) phosphanes and aryl halides or triflates, alkenyl halides, and allyl acetates proceed under palladium catalysis conditions at room temperature or 80 °C in water with THF as a co‐solvent. The coupling reactions give good yields and are highly versatile and chemoselective, allowing the presence of free amino or hydroxy groups in the electrophile. This methodology was applied to the preparation of substituted phenylalanine esters in a demonstration that gold(I) organometallics are suitable reagents for metal‐catalyzed cross‐coupling reactions under protic conditions.

show abstract

“…4‐Methyl‐4′‐(trifluoromethyl)biphenyl (3d): 28 The General Procedure afforded 3d as a white solid (32.5 mg, 0.137 mmol, 93 %), m.p. 131–132 °C.…”

Section: Methodsmentioning

confidence: 99%

Organogold(I) Phosphanes in Palladium‐Catalyzed Cross‐Coupling Reactions in Aqueous Media

Peña‐López¹,

Sarandeses²,

Sestelo³

2013

Eur J Org Chem

View full text Add to dashboard Cite

show abstract

“…Finally, cross-coupling of alkenyl Grignard reagents with vinyl chlorides has been reported in the presence of electron-rich palladium complexes. Representatively, the 1,3-diene 95 is obtained by such a cross-coupling in good yield and in a stereocontrolled manner using PCy 3 (tris(cyclohexyl)phosphine) as ligand [ It may be of interest that other sp 2 electrophiles such as alkenyl phosphates [60], heteroaryl thioethers [61], and aryltrimethylammonium triflates [62] have recently been added to the portfolio of substrates for palladium-catalyzed coupling reactions.…”

Section: Palladium-catalyzed Cross-coupling Reactionsmentioning

confidence: 99%

Carbon–Carbon‐Bond‐Forming Reactions Mediated by Organomagnesium Reagents

Chemla

Ferreira

Pérez‐Luna

et al. 2013

Metal‐Catalyzed Cross‐Coupling Reactions and More

View full text Add to dashboard Cite

IntroductionFirst reported at the beginning of the twentieth century [1], organomagnesiums are very important synthetic tools. In the field of coupling reactions, first examples of transition-metal-mediated reactions have been reported by Gilman and Lichtenwalter [2] with the oxidative homo-coupling of aryl Grignard reagents in the presence of transition metal halides as both catalyst precursors and oxidants. This reaction was later greatly improved by Kharasch [3], who showed that an efficient homo-coupling reaction could be observed with a small amount of CoCl 2 (3 mol%) and an organic halide as a stoichiometric oxidant. This breakthrough was then followed by the report in 1941 on cross-coupling reactions of arylmagnesium bromides with vinylic halides in the presence of various transition metal salts by the same group [4]. Surprisingly, this seminal work remained mainly unexploited, until this reaction was reinvestigated by several groups in the beginning of the 1970s [5]. Thus, Kochi and Tamura [6, 7] described in 1971 the use of Fe(III) salts as catalyst precursors for cross-coupling reactions, while Kumada [8] and Corriu [9] reported the use of nickel for similar transformations [10,11]. At the same time, the group of Normant [12] described the Cu-catalyzed reaction of the Grignard reagents with organic halides, followed by the report of Murahashi [13] on the use of palladium as a catalyst in similar cross-couplings. Most cross-coupling reactions have been performed with unfunctionalized Grignard reagents because no general method for preparing oligofunctional organomagnesium reagents was available. However, the situation is rapidly evolving, thanks to the groundbreaking work of Knochel and coworkers [14] on the preparation of highly functionalized Grignard reagents. In this chapter, the scope and limitations of cross-coupling reactions involving organomagnesium reagents are showcased with select examples from the recent literature with a special focus on functional-group-tolerant procedures. The recent developments of the most challenging transformations including either the use of oligofunctional metallic species or β-hydrogen-containing nucleophiles will be specially highlighted.

show abstract

“…Treatment of syn-7a with phenylmagnesium chloride in the presence of PdCl 2 (PPh 3 ) 2 in refluxing THF provided the 4-phenylsubstituted 1,2-oxazine derivative syn-9 in only 30% yield (Scheme 7). Under ligand-free PdCl 2 -catalyzed conditions 25 no better result was observed and the expected product syn-9 was obtained in 25% yield. To our delight, the Kumada-Corriu coupling could be efficiently improved under microwave conditions.…”

mentioning

confidence: 92%

“…With the aim of preparing a series of 4-substituted 3,6-dihydro-2H-1,2-oxazines, we next focused our attention on the functionalization of nonaflates 6 and enol phosphates 7 using palladium-catalyzed cross-coupling reactions. Initially, we adopted two reported protocols of Begtrup 24 and Skrydstrup 25 describing the use of enol phosphates in palladium-catalyzed Kumada-Corriu couplings. Treatment of syn-7a with phenylmagnesium chloride in the presence of PdCl 2 (PPh 3 ) 2 in refluxing THF provided the 4-phenylsubstituted 1,2-oxazine derivative syn-9 in only 30% yield (Scheme 7).…”

mentioning

confidence: 99%

Convenient Syntheses of Enantiopure 1,2-Oxazin-4-yl Nonaflates and Phosphates and Their Palladium-Catalyzed Cross-Couplings

et al. 2013

View full text Add to dashboard Cite

Efficient methods to prepare enantiopure 1,2-oxazin-4-yl nonaflates and phosphates were elaborated. The corresponding 1,2-oxazin-4-ones were transformed into their enolates and then quenched with nonafluorobutanesulfonyl fluoride or diphenyl chlorophosphate to provide the title compounds. Alternatively, the corresponding α-bromo ketones were subjected to Perkow reactions efficiently leading to the respective enol phosphates. A variety of palladium-catalyzed cross-couplings such as Kumada-Corriu, Sonogashira, Heck reactions or borylation reactions were studied, which delivered the expected new 4-substituted 1,2-oxazine derivatives generally in satisfactory yields. A few typical subsequent transformations were studied including a copper-catalyzed [3+2] cycloaddition with a galactose-derived azide. They demonstrate the synthetic potential of the newly prepared enantiopure 4-substituted 1,2-oxazines.

show abstract

A Ligand Free and Room Temperature Protocol for Pd-Catalyzed Kumada−Corriu Couplings of Unactivated Alkenyl Phosphates

Cited by 71 publications

References 52 publications

Organogold(I) Phosphanes in Palladium‐Catalyzed Cross‐Coupling Reactions in Aqueous Media

Organogold(I) Phosphanes in Palladium‐Catalyzed Cross‐Coupling Reactions in Aqueous Media

Carbon–Carbon‐Bond‐Forming Reactions Mediated by Organomagnesium Reagents

Convenient Syntheses of Enantiopure 1,2-Oxazin-4-yl Nonaflates and Phosphates and Their Palladium-Catalyzed Cross-Couplings

Contact Info

Product

Resources

About