Acetamide allyl

Pd-catalyzed asymmetric allylic alkylation is a typical catalytic carbon-carbon bond forming reaction [ 126 -128]. The Pd-complex of the ligand (R)-3b bearing methyl, 2-biphenyl and cyclohexyl groups as the three substituents attached to the P-chirogenic phosphorus atom was found to be in situ an efficient catalyst in the asymmetric allylic alkylation of l-acetoxy-l,3-diphenylprop-2-en (4) with malonate derivatives in the presence of AT,0-bis(trimethylsilyl)acetamide (BSA) and potassium acetate, affording enantioselectivity up to 96% and quantitative... 

Equation 11.37 Asymmetric palladium-catalyzed allylic alkylation (BSA = N,0-bis(trimethylsilyl)acetamide). 

The cyclization of IV-allyl-o-haloanilines was adapted to the solid phase for both indoles [332, 333] and oxindoles [334]. For example, as illustrated below, a library of l-acyl-3-aIkyl-6-hydroxyindoles is readily assembled from acid chlorides, allylic bromides, and 4-bromo-3-nitroanisole [332], Zhang and Maryanoff used the Rink amide resin to prepare Af-benzylindole-3-acetamides and related indoles via Heck cyclization [333], and Balasubramanian employed this technology to the synthesis of oxindoles via the palladium cyclization of o-iodo-N-acryloylanilines [334], This latter cyclization route to oxindoles is presented later in this section. 

Ethylpentanamide (4.11) and (allyl)(propyl)acetamide (4.12) were also completely biotransformed to the corresponding acids in vivo, but they were... 

Epoxidation of 632c with m-CPBA to 634, followed by silylation with bis(trimethylsilyl) acetamide (BSA) to 635, and TMSOTf-indnced cyclization gives 6-hydroxymethyl-3-phenyl-l,2,4-trioxane 636 (Scheme 181) °. Epoxides 638, which are characterized by geminal dimethyl substitnents, are obtained by m-CPBA oxidation of the (0-3,3-dimethyl-allyl)hydroperoxy acetals 637. While the strnctnral change in 638, as compared to epoxide 634, direct the acid-catalyzed cyclizations to the endo mode yielding the 7-membered... 

The chiral nonracemic bis-benzothiazine ligand 75 has been screened for activity in asymmetric Pd-catalyzed allylic alkylation reactions (Scheme 42) <20010L3321>. The test system chosen for this ligand was the reaction of 1,3-diphenylallyl acetate 301 with dimethyl malonate 302. A stochiometric amount of bis(trimethylsilyl)acetamide (BSA) and a catalytic amount of KOAc were added to the reaction mixture. A catalytic amount of chiral ligand 75 along with a variety of Pd-sources afforded up to 90% yield and 82% ee s of diester 303. Since both enantiomers of the chiral ligand are available, both R- and -configurations of the alkylation product 303 can be obtained. The best results in terms of yield and stereoselectivity were obtained in nonpolar solvents, such as benzene. The allylic alkylation of racemic cyclohexenyl acetate with dimethyl malonate was performed but with lower yields (up to 53%) and only modest enantioselectivity (60% ee). 

Zur Herstellung von 1,2-Diamino-propanen in hoher Ausbeute eignet sich die Ami-nomercurierung-Demercurierung von N-Allyl-acetamid mit Anilin oder substituierten Anilinen, gefolgt von Hydrolyse der Amid-Gruppierung2 ... 

Acetamide N-Methyl-N-(2-phenyl-allyl)-trifluoro- ElOb, 643 (NH - N-CO-CF )... 

Displacement of allylic gem -diacetates.1 In the presence of Pd(dppe)22 as catalyst and 0,N-bis(trimethylsilyl)acetamide as base, one acetoxy group of an allylic gem-diacetate can be displaced by a stabilized nucleophile. 

Scheme 2.27 Enantioselective molybdenum-catalysed allylic alkylation of linear arylpropenyl carbonates (BSA = N, O-bis(trimethylsilyl)acetamide).

The decarboxylative Claisen rearrangement of allylic tosylacetate (5) and methyl tosylmalonate derivatives has been extensively studied. In the tosylacetate series, it has been found that acetate ions, base and a silylating agent, preferably N,0-bis(trimethylsilyl)acetamide (BSA), are all necessary, but in only catalytic quantities provided that BSA is used. Potassium acetate has been shown to be a suitable base. 

Hence, N,N-diallyl-(2-chlorophenyl)-amine and N-allyl-N-(2-chlorophenyl)-acetamide react with MesSn and Ph2P ions in liquid ammonia under photostimulation to afford cyclized-substituted compounds in good yield (Scheme 10.51) [67]. 

The palladium-catalysed allylic alkylation of dimethylallyl acetate 35 with dimethyl malonate 36 in THF at 25°C was carried out using a combination of Pd2(dba)3 [fris(dibenzylideneacetone)dipalladium] and triphenylphosphine with 0,N-Ws(trimethylsilyl)acetamide (BSA) as a base.87... 

Nagashima and colleagues showed subsequently that 5-10 mol% of Pd(PPh3)4 catalyzed atom transfer radical cyclizations (ATRC) of /V-allyl-difluoroiodo-acetamides 158b in fluorescent lab light at ambient temperature [194], Under these conditions, 34—98% yield of cyclized compounds 159b were obtained. No reaction occurred in the dark, while it was considerably slower in the absence of the catalyst. The low yield of 34% in one example (R=Bn) is due to the unfavorable rotational barrier in the substrate, which cannot be influenced by the presence of the catalyst. 

A new approach to the abe ring system of the pentacyclic C20 diterpenoid alkaloids has been reported by van der Baan and Bickelhaupt.51 For the model system of major interest, (134) was prepared from (133) by reaction with cyano-acetamide. Treatment of (134) with allyl bromide gave almost exclusively C-alkylation, to afford (135). On heating (135) at 100—110°C, a Cope-type rearrangement to (136) was effected. This compound was then N-alkylated with ethyl iodide-DMF, the product being (137). Treatment of (137) with IV-bromosucc-... 

Dienes. Allylic acetates when heated in toluene with Mo(CO), and bis(trimethylsilyl)acetamide (BSA) are converted into 1.3-dienes by loss of acetic acid. The reaction is most u ful when only one diene can be formed. It provides one step in a transformation of aldehydes into dicnoates. 

Macrocyclization by allylation-alkylotion. The key step in a synthesis of the antibiotic A26771B (3) is cyclizationof the substrate 1 using O.N-bis(trimethylsilyl)acetamide (1, 61 2, 30 3, 23-24) as base and Pd[P(ChH,),]4 as catalyst. In addition a bidcntate phosphorus ligand is essential. The highest yields were obtained with 1,4-bis(diphenylphosphine)butane (dppb). 

Allylic alkylation. In general, ally lie alkylation catalyzed by transition metals results from attack at the less substituted carbon atom of the TT-allyl intermediate. Deviation from this pattern is observed with some nucleophiles when Mo(CO)6 is used as catalyst. For example, the anion of dimethyl malonate generated with 0,N-bis(trimethylsilyl)acetamide (BSA) reacts with the allylic acetate 1 mainly by attack at the tertiary center to give 2. 

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