Addition to methyl acrylate

For acyclic nitronates, the reaction rate can depend on the configuration of the dipole. On the basis of 15N NMR spectroscopic data, it was demonstrated (338a) that thermodynamically more favorable lruns isomers of nitronates (1) are much less reactive in [3+ 2]-addition to methyl acrylate (Scheme 3.128). 

To 0.2 mole of an olefin dissolved in 30 ml of glacial acetic acid is added 19.5 gm (0.3 mole) of sodium azide in 75 ml of water. The addition to acrolein and jf -nitrostyrene underwent rapid addition, requiring cooling with an ice-salt bath and slow addition of the sodium azide. Addition to methyl acrylate, acrylic acid, and acrylonitrile required 1-3 days at room temperature, a-vinyl pyridine and mesityl oxide required heating for 24 hr on a steam bath. Other olefins underwent no reaction even after 7 days of heating and were recovered unchanged. 

Shi and Xu reported that the chiral amine catalyst 142 also performs quite efficiently in the related addition of N-tosyl aryl imines to methyl vinyl ketone (MVK), to methyl acrylate, and to acrylonitrile (Scheme 6.61) [155]. As shown in Scheme 6.61, enantiomeric excesses > 95% were achieved for several />-N-tosylamino enones 147 obtained by addition of aryl imines (146) to MVK, > 80% for addition to methyl acrylate, and 55% ee (max.) for addition to acrylonitrile (not shown in Scheme 6.61). Reaction times were typically 1-3 days. N-Sulfonylimines derived from aliphatic aldehydes gave rise to complex product mixtures. Under the reaction conditions shown in Scheme 6.61 addition of p-nitrobenzaldehyde to MVK proceeded with only 20% ee. 

Belokon and co-workers designed a glycine-derived nickel complex 60 and examined its asymmetric addition to methyl acrylate under phase-transfer conditions. The screening of various NOBIN and iso-NOBIN derivatives in combination with NaH as a base revealed that N-pivaloyl-iso-NOBIN (62b) proved to be highly efficient catalyst, affording the product 61 in 80% yield with 96% ee, as illustrated in Scheme 4.20 [59]. 

Starburst polyamidoamine (PAMAM) synthesis [2, 77-81, 83] may begin with either a nucleophilic or an electrophilic core. In the case of nucleophilic cores such as ammonia or amine, step A in Scheme 21 involves exhaustive Michael addition to methyl acrylate. This addition occurs very rapidly and in high yield with essentially complete selectively and no amidation at room temperature. Step B requires addition of this triester intermediate to a large excess of ethylenediamine at room temperature to produce the terminal triamine core cell shown in Fig. 2 and Scheme 21. Repeating the sequence of steps A and B leads, via a hexaester... 

Other lithiated vinyl sulfides bearing a carbonyl group at the / -position have been used in organic synthesis mainly as /3-acyl vinyl anion equivalents858. The 2-(isopropylsulfanylmethylene) derivative 673 has been deprotonated with lithium 2,2,6,6-tetramethylpiperidide (LiTMP) to give the intermediate 674 which, after addition to methyl acrylate and final hydrolysis, afforded the cyclopentenone 675 in 70% overall yield981 (Scheme 175). 

An example of conjugate free-radical addition to methyl acrylate mediated by a copper Lewis acid has been reported (Sch. 30) [65]. In this example the Lewis acid 127 activates the substrate for conjugate addition by the aryl radical which is followed by an enantioselective chlorine atom-transfer step. Chemical and optical yield for the transformation are both low. 

The main product in hydrosilation of a,P-unsaturated ketones and aldehydes catalyzed by chloro-platinic acid, platinum on alumina, or metallic nickel is the corresponding silyl enol ether. With nickel catalyst, product distribution is highly dependent on the enone structure. Hydridosilanes add to a, -unsaturated esters, producing the corresponding silyl enolate as well as carbon silylated products. The course of addition depends on substrate structure and the hydridosilane utilized. Thus, triethylsilane undergoes 1,4-addition to methyl acrylate in the presence of chloroplatinic acid, while trichlorosilane with either chloroplatinic acid or Pt/C gives the -silyl ester (Scheme 65). ... 

The chiral moiety of the nitrone can also be located at the carbon atom. Yokoyama et al. [50] used this approach in the asymmetric synthesis of spiro isoxazohdines (Scheme 10.21). The ribose-derived nitrone 62 is obtained from the corresponding oxime by Michael addition to methyl acrylate. With a second equivalent of methyl acrylate, the sugar nitrone 62 gave a single cycloadduct 63, which was converted into the corresponding pyrrolidine by reduction. 

The radical produced by addition to vinyl acetate is nucleophilic, so it adds to methyl acrylate the radical produced by addition to methyl acrylate is electrophilic, so it adds to vinyl acetate. This reaction is a clear... 

Addition to methyl acrylate. The ester required for this reaction was obtained from a 60% solution in methanol supplied by Rohm and Haas. This solution was treated with hydroquinone and washed repeatedly with 7% aqueous sodium sulfate solution to remove the methanol, and the ester was dried, filtered, and used without distillation. For the preparation of methyl -bromopropionate, hydrogen bromide... 

L-(+)-Tartaric acid (F) was then converted to iodide G, whose addition to methyl acrylate under the standard conditions of radical reactions furnished H. Hydrogenolysis of H over palladium black yielded the corresponding alcohol, whose Swern oxidation afforded I, another building block. 

A variety of useful electrophilic substitutions of 3-trimethylsilylindoles were reported by Majchrzak and Simchen152. Of particular interest is the ability to bring about the 1,4-addition to methyl acrylate, acrolein and enones (equations 158 and 159). 

Reduction of an alkylmercury halide or acetate with a borohydride provides an alternative method for accessing a carbon radical species (see Scheme 4.11). The alkylmercury compound can be prepared by one of a number of methods, such as from the corresponding Grignard reagent or from addition of Hg(OAc)2 to an alkene. For example, intramolecular amido-mercurafion of the alkene 50, followed by formation of the alkyl radical and addition to methyl acrylate provides a route to the alkaloid 8-coniceine (4.46). ... 

The required ketosulfoxide 69 (Scheme 15) was obtained in two steps in a one-pot procedure from 1,4-dimethoxybenzene (66). Ortho Hthiation of 66, lithium-copper exchange, and addition to methyl acrylate gave ester 67. Reaction of the anion obtained from (R)-methyl(p-tolyl)sulfoxide (68) [89] by treatment with LDA, with ester 67 afforded ketone 69. Diastereoselective addition of diethylaluminum cyanide to the carbonyl group of 69 [90] furnished sulfinylcyanohydrin 70 as the sole product. The (S) configuration of the new stereogenic center was inferred from the previous studies of acycUc P-ketosulfoxides [91,92]. 

In a much more recent report, conveniently O-protected a-hydroxymethyl aryl ketones were also successfully employed as Michael donors in the conjugate addition to methyl acrylate and acrylonitrile using a cinchonine-based ammonium salt as catalyst. Bis-quinidine-based ammonium salt 105 has also shown to be useful in the reaction of cyclic p-ketoesters to methyl and ethyl acrylate. ... 

The resulting anion effects a conjugate addition to methyl acrylate. 

Addition to methyl acrylate has also been found to occur, the sulfoxide (30) giving the epimeric mixture 123 and 124 (U. S. Patent 4,115,383 Bachi et al., 1978). Even when methyl acrylate was used as solvent, the reaction could not be driven to completion, approximately 10% of the sulfoxide remained (U. S. Patent 4,115,383). Compounds 123 and 124,... 

Birch reductions of alkyl benzoates are not normally feasible due to the preference for Bouveault-Blanc-type reduction of the ester group. However, it has now been found that if one to two equivalents of water are added to the ammonia before addition of the metal, then good yields of cyclohexadiene-esters [e.g. (191) from ethyl benzoate] can be realised. It is known that Birch reductions of benzoic acids can be used to generate dianonic species (192). These have been found to undergo conjugate additions to methyl acrylate and... 

Cyclopropanecarboxylic esters have been prepared, in 75—86 % yield, by intramolecular alkylation of 4-chloroalkyl esters, using phase-transfer catalysis. Monoalkylation of nitro-alkenes by acrylic esters occurs in a controlled manner if a two-phase system is used, to give products of Michael addition in 45—65 % yield for five examples. An interesting variant on this reaction involves the generation of the a-nitro-carbanion by conjugate reduction of a nitroalkene with sodium borohydride followed by its conjugate addition to methyl acrylate yields of 62—95% are reported for five cases (Scheme 39). ... 

Photolysis of tri-O-benzyl glucal-derived 384 generated the acetaloxyalkyl radical 385, which undergoes conjugate addition to methyl acrylate affording the product of an overall atom transfer process 386. Desulfuration and auxiliary cleavage with concomitant lactonization affords the (known) lactone 387 (Scheme 61). The diastereoisomeric excess of 386 was not reported. 

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