Ethyl 2-bromomethylacrylate

When the Pd-catalyzed exchange protocol was applied to the 5-alkenyl iodides of type 51, the cyclized organozinc reagents 52 were directly obtained and functionalized by allylation with ethyl 2-bromomethylacrylate after transmetallation with CuCN 2LiCl. The five-membered ring products 53 were obtained with high trans diastereoselectivity, irrespective of the nature of the allylic substituent (R = Ph or OBz) at the allylic position (equation 21)34,39. By contrast, the zinc-induced carbocychzations were found to be moderately cis stereoselective when an acyloxy group was present at the allylic position (see Section II.B.2)29. 

Secondary alkyl iodides bearing an additional substituent at the allylic position underwent highly diastereoselective Pd-catalyzed carbozincations, as illustrated for 56 which led after allylation with ethyl 2-bromomethylacrylate to the trisubstituted cyclopentane 57 (C1-C2 trans/cis > 99/1, C2-C3 cis/trans = 95/5) (equation 23)39,40. 

K-Allylnickel ImBiles (2, 291), Walter and Wilke reported briefly that Ni(COD)2 is more reactive than nickel carbonyl in the reaction of allylic halides to form 71-allyl-nickel halides. The reaction proceeds below 0° and in quantitative yields. The method has not been used extensively since nickel carbonyl is commercially available. However, Semmelhack recommends use of Ni(COD)2 for the preparation of thermally sensitive a-allyinickel halides such as it-(2-carbocthoxyallyl)nickel bromide," which was prepared from ethyl 2-bromomethylacrylate with this nickel reagent in 76% yield. 

Ethyl bromide, 287 Ethyl 2-bromomethylacrylate, 33 Ethyl 3-bromopropyl acetaldehyde acetal, 226-227... 

Rather unexpectedly, ethyl 2-bromomethylacrylate did not give the simple dichlorocarbene adduct. The conditions were changed during the course of the reaction and a multistep process accounts for the formation of the isolated product 3. ... 

A one-pot synthesis of telechelic and semitelechelic poly(alkyl acrylates) with unsaturated end groups has been developed by Bielawski et al. [1]. ATRP of methyl acrylate or -BA was initiated with either ethyl cy-bromomethyl-acrylate or methyl dichloro acetate, as a monofunctional or a difunctional initiator, respectively, and was mediated with various Cu-amine complexes. Addition of excess ethyl 2-bromomethylacrylate was found to immediately quench the polymerization, but also to insert 2-carbethoxyallyl moieties at the ends of the polymer chains (Scheme 24). Thus, the synthesis of telechelic poly(alkyl acrylates) with unsaturated end groups has been accomplished, with very good functionality (f 2) (Scheme 24). 

Ballini et al have reported a rapid diastereoselective MBH reaction by using nitroalkenes 91 as activated alkenes, ethyl 2-bromomethylacrylate 92 as electrophilic acceptor and DBU as base catalyst. Nitro dienes 93 were obtained in good yields and very short reaction times. Moreover, starting from appropriate nitroalkenes it is possible to realize a one-pot synthesis of trienic systems 94 (Scheme 2.39). ... 

Figueredo and coworkers were driven by the total synthesis of a polycyclic natural molecule (the putative structure of stemonidine) [22] when they reported their Reformatsky-type reaction for the diastereoselective construction of spiro-a-methylene-y-butyrolactone 48. Reaction of the starting ketone 47 with ethyl bromomethylacrylate and zinc led to the formation of the desired spirolactone 48 in 86% yield and with complete facial selectivity (Scheme 9.13). 

Conceptually similar a,a -annulations of ketone enamines have also been carried out with electrophilic alkenes containing a reactive allylic halogen, such as ethyl a-bromo-methylacrylate or dimethyl y-bromomesaconate318-320 (Scheme 156). An elegant one-pot synthesis of the adamantane ring system involving sequential double Stork and Dieckmann reactions has been developed by Stetter and Thomas321 (Scheme 157). Reaction of the bis-enamine 154 with ethyl a-bromomethylacrylate leads to the pentacy-clic system 155322 (Scheme 158). 

Abarbi et al. (OOJOC4618) reacted 3-bromopropene and 2-bromomethylacrylic acid ethyl ester with the Grignard reagent derived from 1,5-dimethyl-3//-5-iodo-2-phenylpyrazol-3-one and diisopropyl magnesium, and obtained the corresponding 4-allyl-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one and 2-(l, 5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-17/-pyrazol-4-ylmethyl)acrylic acid ethyl ester, respectively. 

The reaction of malonate enolates with cyclohexane epoxides leads to mixtures of the two possible lactones (87) and (88)," convertible into the corresponding a-methylene-lactones by now relatively standard procedures. In a similar vein, the bis-spirolactone (90) can be obtained from epoxide (89). Spirolactones can also be prepared from cyclic ketones by condensation with ethyl a-bromomethylacrylate in the presence of zinc, and cyclization of the adduct in cold, dilute acid." ... 

Compared to tin-mediated allylation in ethanol-water mixture, the indium procedure is superior in terms of reactivity and selectivity. Indium-mediated allylation of pentoses and hexoses produced fewer by-products and was more diastereoselective. The reactivity and the lAreo-selectivity, compatible with a chelation-controlled reaction, were even improved when preformed allyl-dichloroindium was allowed to react with ribose in an ethanol-water mixture (Kim et al, 1993). As an application of the indium methodology, a diastereoselective three erythro = 4/1) allylation of /V-acetyl-p-D- mannosamine (Scheme 4.4) with ethyl a-bromomethylacrylate and indiiun in a mixture of ethanol and 0.1 N aqueous hydrochloric add could be achieved, allowing a straightforward synthesis of /V-acetylneuraminic acid, the sialic acid that... 

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