2-Methylene esters

Microwave irradiation accelerates the rate of Mg(II)-catalysed 1,3-dipolar cycloaddition between mesitonitrile oxide and jS-hydroxy-2-methylene esters, but has little effect on the diastereoisomeric excess. FMO interactions and regiochemical drift due to steric effects have been used to determine the regiochemistry of 3 + 2-cycloadditions of nitrile oxides with a,/3-unsaturated amides. The gas-phase 1,3-dipolar cycloaddition of fulminic acid to ethyne has been investigated using valence-bond theory in the spin-coupled form and using intrinsic reaction... 

Peroxy benzoic Acid, 1,1,4,4-Tetramethyltetra-methylene Ester. See 2,5-Bis(Benzoylperoxy)-2,5-dimethyl-hexane in Vol 2, B135-R... 

Dipolar cycloadditions of ( -phenyl-/V-methylnitrone (585) to Baylis-Hillman adducts such as ( 3-hydroxy-a-methylene esters) (608-610) proceed with complete regioselectivity in good yields to afford the corresponding diastere-omeric 3,5,5-trisubstituted isoxazolines (611-613) (Scheme 2.269). Attack by the dipole in (585) from the less sterically hindered side of dipolarophiles (608-610) affords C-3/C-5 cis isoxazolidines (611a,b-613a,b) as the major products (780). 

Primary and secondary alcohols are oxidized slowly at low temperatures by benzyltriethylammonium permanganate in dichloromethane primary alcohols produce methylene esters (60-70%), resulting from reaction of the initially formed carboxylate anion with the solvent, with minor amounts of the chloromethyl esters and the carboxylic acids. Secondary alcohols are oxidized (75-95%) to ketones [34] the yields compare favourably with those obtained using potassium permanganate on a solid support. 1,5-Diols are oxidized by potassium permanganate under phase-transfer catalytic conditions to yield 8,8-disubstituted-8-valerolactones [35] (Scheme 10.1). 

Xu, R., Leonard J., and Bui, V.T. Vapor pressure for mixtures of methylene ester oligomers with /rdioxane and chloroform, /. 

The aldehyde can be replaced by an imine and the reaction is then called the aza-Baylis-Hillman reaction [87, 88]. (3-Amino-a-methylene structures obtained in this way could further be converted to a range of biologically important molecules, such as p-amino acids [89]. First reaction of this kind was published in 1984 [90]. Tosylimines and ethylacrylate reacted in the presence of DABCO as catalyst to give p-aminoesters. First three-component aza-Baylis-Hillman reaction was published in 1989 by Bertenshaw and Kahn [91], with imine formation in situ from an aldehyde and an amine. In the presence of triphenylphosphine as catalyst, the reaction with methylacrylate led to the formation of the p-amino-ot-methylene esters and ketones in good yields (Scheme 38). 

Aggarwal and coworkers have studied the electrophilic behavior of enantiomerically pure N-p-toluenesulfinimines and N-tert-butanesulfinimines in the asymmetric Baylis-Hillman reaction with methyl acrylate with and without Lewis acids [26], In the presence of In(OTf)3 good yields and high diastereoselectivities have been achieved providing an effective route to /i-amino-a-methylene esters. 

Radical-mediated reaction of 7-hydroxy or 7-alkoxy-a-methylene ester (21) with iso-Prl in the presence of MgBr2 gives the yyrc-adduct (22a) predominantly via the intermediate [V] as shown in eq. 10.11. The same chelation-controlled radical 1,3-stereo... 

Several indium-mediated intramolecular carbonyl allylation reactions have been investigated, and it has been found that these reactions provide an easy access to a variety of cyclic compounds. The intramolecular cyclization of 49a-c mediated by indium in aqueous media proceeds smoothly to afford carbocyclic systems containing y-hydroxy-Q -methylene esters 50a-c, which either spontaneously or readily cyclize to give fused o -methylene-y-butyrolactones 51a-c (Scheme 52). The same cyclization of 49d is too slow to compete with the side-reaction, in which the bromide is substituted by a hydroxy group. The ring junction stereochemistry of fused lactones 51 has been found to be cis in all cases. Of the two possible transition states, the one leading to the m-fused compounds is preferred, because the chair-chair conformation is favored over the chair-boat conformation.209... 

This methyl methylene ester, which boils less than 10° below the desired isomer, can be separated by careful fractionation through an efficient column such as the 1.5-m. simple Podbielniak-type column.3 The esters are more easily fractionated than are the higher-boiling acids. 

The methylene ester of 6-nitro-2,l-benzoxazole-3-carboxylic acid is obtained in a similar manner [434], The reaction of oxidation of 1,3,5-trinitrobenzene a-complexes, containing the C-C bond in the side chain, follows an interesting pathway [434],... 

The same method can he used to convert a-nitro esters into a-methylene esters, except that the hydroxymethylation step is catalyzed with sodium hydroxide rather than triphen-ylphosphine. 

Deacylative condensation a-methylenation Reaction of the carbanion of a-alkylated 8-keto esters with paraformaldehyde in THF at -78° initially and finally at reflux leads to -methylenated esters (equation I). 

Amino-hydra zino-methylen)- -diester E15/1, 784 (CC13 -+ NH-NH2) [(Amino-morpholino-methylen-amino)-arylamino-methylen]- -ethylesternitril- E15/2, 2140 (SR - N = CR-NH2) (Amino-organooxy-methylen)- -ester-nitril E15/2, 1804 [(NC)2NH - COOR + R - OH] (3-Anilino-2-propinyliden)- -nitril E15/3, 3366... 

SYNS ENT 51,799 METHANESULFONIC ACID, METHYLENE ESTER O METHYLENE BIS(METHANE-SULFONATE)... 

The N-1 methyl group may be replaced by aroylmethyl or methylene ester substituents, as in (125). High affinity is maintained and... 

The a-silylmethyl esters (252), potentially useful as precursors to ot-methylene esters can be prepared by additions of l-ethoxy-3-trimethylsilyl-l-propyne to a wide variety of both saturated and... 

The cyclocondensation of 1,2-diketones, reactive a-methylene esters and hydrazines leads, in its simplest form as a one-pot reaction, to pyridazin-3(2//)-ones 11 (Schmidt-Druey synthesis) ... 

In another study, Eisera et al. studied the same nitrone, 130, in 1,3-dipolar cycloadditions to j8-hydroxy-a-methylene esters 150 under thermal heating or microwave... 

Synonyms MBT Methylene dithiocyanate MTC Thiocyanic acid, methylene ester... 

CAS 2227,- 2-1 , EINECS/ELINCS 218-741-5 Synonyms Acrylic acid 3-acryloyloxy-2,2-dimethylpropyl ester Dimethylolpropane diactylate 2,2-Dimethylpropane-1,3-diacr te 2,2-Dimethyl-1,3-propanedk)l diactylate 2,2-Dimethyl-1,3-propanediol diester acrylic acid 2,2-Dimethyltrimethylene acrylate 2,2-Dimethyltri-methylene ester acrylic acid NPGDA 2-Propenoic acid-2,2-dimethyl-1,3-propanediyl ester ClassiTication Nonaromatic ester Empirical C H,60,... 

Hexadecanoic acid, 1-methylethyl ester. See Isopropyl palmitate Hexadecanoic acid, (6-methyl-5-((1-oxohexadecyl) oxy)-3,4-pyridinediyl) bis (methylene) ester. See Pyridoxine tripalmitate Hexadecanoic acid, 1-m hyl pentyl ester. See Isohexyl palmitate... 

Thiocyanomethylthiobenzothiazole Thiocyanic acid, 1-chloro-1,2-ethanediyl ester Thiocyanic acid, chloroethylene ester. See Chloroethylenebisthiocyanate Thiocyanic acid compd. with guanidine (1 1). See Guanidine thiocyanate Thiocyanic acid, 1,2-ethanediyl ester. See Vinylene bisthiocyanate Thiocyanic acid, methylene ester. See Methylenebis (thiocyanate)... 

A -aIlyl- 3-amino-a-methylene esters were produced in good yields and enantiose-lectivities using 20 mol% of commercially available quinidine (Scheme 11.39). Further potential of the method could be inferred from the ring-closing metathesis (RCM) of adducts, using Zhan 1-B catalyst (5 mol%), to yield enantioenriched 2,5-dihydropyrroles without loss of optical purity. 

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