Vinyl triflates amidations

Palladium complexes also catalyze the carbonylation of halides. Aryl (see 13-13), vinylic, benzylic, and allylic halides (especially iodides) can be converted to carboxylic esters with CO, an alcohol or alkoxide, and a palladium complex. Similar reactivity was reported with vinyl triflates. Use of an amine instead of the alcohol or alkoxide leads to an amide. Reaction with an amine, AJBN, CO, and a tetraalkyltin catalyst also leads to an amide. Similar reaction with an alcohol, under Xe irradiation, leads to the ester. Benzylic and allylic halides were converted to carboxylic acids electrocatalytically, with CO and a cobalt imine complex. Vinylic halides were similarly converted with CO and nickel cyanide, under phase-transfer conditions. ... 

For conversion of vinylic triflates to carboxylic esters and amides, see Cacchi, S. Morera, E. Ortar, G. Tetrahedron Lett., 1985, 26, 1109. 

The palladium-catalyzed coupling of vinyl triflates with amides, carbamates, and sulfonamides has been reported by researchers at Merck.119 They identified Xantphos as the best ligand for this reaction. The product enamides serve as valuable synthetic intermediates as they can undergo asymmetric hydrogenation to give enantiopure amines. 

Willis has similarly noted that indoles can be prepared via the cascade coupling of the aryl-halide and vinyl-triflate bonds in styrene 21 with primary amines (Scheme 6.41). Despite the fact that two different types of C—X bonds must be activated, this process proceeds with a single palladium catalyst (Pd2dba3/Xantphos), and a range of primary amines, carbamates and amides. More recently, even vinyl chlorides were found to participate in this coupling reaction [53]. 

Lactams are amides in four-membered rings and are common elements found in antibiotics. Show what reagents would be involved in creating the following series of )3-lactams using a common vinyl triflate in each case. 

HMDS is known as an ammonia substitute in the preparation of primary amides via ammonolysis since 1985. With the use of excess HMDS, the Pd-catalyzed aminocarbonylation of various aryl and vinyl iodides and triflates (e.g., 146, 148, and 150) has been successfully performed to give the corresponding vinyl and aryl amides (e.g., 147, 149, and 151, respectively) in good to excellent yields (Scheme 21). " ... 

Muratake et al. reported the intramolecular a-arylation of ketones [55,56]. Thus, polycyclic compounds are readily obtained from aromatic keto-bromides and keto-triflates (Eq. 16). Bromo-amides can give the corresponding cycliza-tion products (Eq. 17) [52]. Related intramolecular vinylation reactions to give aliphatic polycyclic compounds have also been reported (Eq. 18) [57,581. The intramolecular cyclization of aromatic halo-ketones under carbon monoxide, which proceeds by mechanism C, gives the corresponding a-acylated products (Eq.l9) [321. 

The original procedure involved the coupling of aryl bromides with secondary amines. However, since then the scope has been expanded to include substrates such as aryl iodides, chlorides, fluorides, triflates, tosylates, nonaflates, iodonium salts, and even boronic acids. While the reaction has not been extensively utilized with vinyl or alkynyl substrates, it can be performed with various heteroaryl halides. Similarly, numerous types of nitrogen-containing coupling partners, including primary amines, imines, various azoles, lactams, and simple amides, can now be used in this reaction. 

In the Heck reaction, aryl, heterocyclic and vinyl halides - " or aryl triflates react with excess carbon monoxide and primary or secondary amines to give substituted amides, in the presence of a palla-dium(II) catalyst (equation 41). Cis- and trans-vinyl halides react stereoselectively. 

The present methods for the preparation of N acyl a arylenamides include (i) reductive acylation of ketoximes with iron metal [2] or phosphines [3] in the presence of acyl chlorides or acyl anhydrides (Method A) (ii) metal catalyzed coupling of vinyl halides [4], triflates [5], or tosylates [6] with amides (Method B) (iii) reaction of imine intermediates derived from nitriles with acyl chlorides or anhydrides (Method C) [7] and(iv) Pd catalyzed coupling ofaryl tosylates with N acyl vinylamines (MethodD) [8]. 

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