Addition, homoconjugate

HOMOCONJUGATE ADDITION OF NUCLEOPHILES TO CYCLOPROPANE-1,1-DICARBOXYLATE DERIVATIVES PREPARATION OF 2-OXO-1-PHENYL-3-PYRROLIDINECARBOXYLIC ACID... [Pg.34]

HOMOCONJUGATE ADDITION, 66 Homo-Michael acceptor, 69 Hydrogen peroxide-acetonitrile, 63 4-Hydroxy-2-butanone, 93... [Pg.70]

HOMOCONJUGATE ADDITION, 60, 66 Homo-Michael acceptor, 60, 69 Hydrazine hydrate, 61, 17 Hydrazine monohydrate [7803-57-8], 61, 17 HYDROC1NN AM ALDEHYDE, a-METHYL-, 61,82... [Pg.81]

Homoconjugative addition. Benzenesulfenyl chloride adds to 5-methylene-2-norbornene (1) to give 1 -chloromethyl-3-nortricyclyl phenyl sulfide (2) in good yield. ... [Pg.325]

Another example of this homoconjugate addition is the reaction of ethyl a-cyano-cyclopropanecarboxylate (4) with 2 eq. of divinylcopperlilhium to give ethyl 2-cyano-5-hexenoate (5) in 70% yield. [Pg.219]

Homoconjugate additions of secondary amines to cyclopropyl ketones catalysed by acid have been reported as well as formation of certain 5,6-dihydro-4H-l,2-oxazines with hydroxylamine hydrochloride. Demuth and Mikhail have recently demonstrated that cyclopropanes of the tricyclo[3.3.0.0 ] octan-3-one type can be selectively converted to functionalized bicyclic compounds with different kinds of electrophilic/nucleophilic reagents (equation 41) the products have extensively been exploited for natural product synthesis ". ... [Pg.387]

Hexyne, 159,231, 253 Homoconjugate addition, 219 Homogeranyl cyanide, 111, 112 Homologation, 272, 369 Horner-Wittig reaction, 61 Huang-Minlon reduction, 248 Hunsdiecker reaction, 279 Hunsdiecker-Cristol reaction, 323-324 Hydrazine, 26,248, 395 Hydrazine hydrate, 155, 336 Hydrazoic acid, 440... [Pg.325]

Homoconjugate addition to cyclopropanes. Corey and Fuchs2 have investigated the reaction of cyclopropanes with organocopper reagents as a possible synthetic route to prostanoids. For example, the tricyclic lactone ester (1) reacts with divinylcopper-lithium (2.0 eq.) in ether at -12° (19 hr.) to give the vinylcyclopentane lactone ester (2). This product was treated directly with lithium iodide (5 eq.) in pyridine (1,615-616) at reflux for 3 hr. to give the lactone (3) in about 37% yield. [Pg.447]

Danishefsky and co-workers have used activated cyclopropanes to promote intramolecular alkylation of an amino function, followed by lactam formation to provide a new entry to the pyrrolizidine ring system.20 This route is outlined in Scheme 1. Cyclopropanation of the phthalimido-olefin (19) was achieved with dimethyldiazomalonate in the presence of copper bronze. Treatment of the cyclopropane derivative (20) with hydrazine released the amine, which gave the lactam ester (21) in quantitative yield. This corresponds to intramolecular homoconjugate addition entirely in the spiro mode.21 It seems reasonable that the first step in this process is internal alkylation of the amine by the activated cyclopropane. The alternative... [Pg.254]

Another mechanistic possibility that has been proposed with Mgl2- and Lil-promoted annulations of (3-ketoester cyclopropanes 22 involves the bis-coordination of the p-ketoester group to magnesium followed by homoconjugate addition of iodide ion to the VCP, forming an allyl iodide intermediate 23. The (E)-isomer of this intermediate can only revert back to the VCP via an 5 2 pathway, whereas the (Z)-isomer would undergo intramolecular 5 2... [Pg.407]

These intramolecular homoconjugate additions provide a simple entry into fura-noid systems. The p-keto-ester (461) cyclizes in a spiro mode to (462a), whereas with dimsylsodium the isomer (462b) is formed. Similarly, the keto-ester (463 R = COjMe) is cyclized to (464) by sodium hydride, but the ketone (463 R = H) affords only the Dieckmann product (465) under these conditions. ... [Pg.99]

Pyrrolizidines and indolizidines are also available by this type of reaction, from the amines liberated by the action of hydrazine on the phthalimides (466 n = 3 or 4). No intramolecular homoconjugate addition was observed for the lower homologue (466 n = 2), however, the lactam (467) being the only product. ... [Pg.99]

Homoallyl rearrangement, geospecific, ethynyl group-controlled 17, 611 suppl. 27 Homoconjugate addition s. Addition, homoconjugate Homoelectrocyclic reactions 26,126... [Pg.285]

In 2013, Fox and co-workers reported an enantioselective synthesis of cyclobutanes based on a sequential rhodium-catalysed bicyclobutanation-copper-catalysed homoconjugate addition-enolate trapping reaction. Indeed, a range of enantiomerically enriched functionalised cyclohutanes were constructed through this one-pot three-component process in which t-butyl... [Pg.76]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...