Copper-catalysed reactions of allylic grignard reagents with epoxides.

Linstrumelle, G.; Lorne, R.; Dang, Huu

doi:10.1016/s0040-4039(01)95142-1

Cited by 38 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under CuI catalysis an unsymmetrical allylic Grignard reagent, such as prenylmagnesium chloride, is known to react through the less substituted allylic terminus with an epoxide. 6 Indeed, the reaction to give chlorohydrin 4d has previously been carried out on about a 1-mol scale. 7 Coupling of epichlorohyrin with prenylmagnesium chloride in the absence of a copper salt occurred through the more substituted allylic position to give chlorohydrin 4e, as anticipated from the reaction of this Grignard reagent with other epoxides.…”

mentioning

confidence: 99%

“…7 Coupling of epichlorohyrin with prenylmagnesium chloride in the absence of a copper salt occurred through the more substituted allylic position to give chlorohydrin 4e, as anticipated from the reaction of this Grignard reagent with other epoxides. 6 Using such chlorohydrins as potential cyclopropanation precursors was found to offer an added practical advantage when compared to using the corresponding low molecular weight terminal epoxides. This is because the latter have volatility issues during isolation, but the corresponding chlorohydrins are much less volatile, making them easier to isolate.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Intramolecular Cyclopropanation of Epichlorohydrin-Derived Unsaturated Chlorohydrins

Hodgson¹,

Chung²,

Paris³

2005

Synthesis

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Intramolecular Cyclopropanation of Epichlorohydrin-Derived Unsaturated Chlorohydrins

Hodgson¹,

Chung²,

Paris³

2005

Synthesis

View full text Add to dashboard Cite

show abstract

“…ethanols [298,299], and oxymethyl oxirane derivatives (e.g. glycidol derivatives) [300,301], which are also quite resistant toward rearrangement.…”

Section: Epoxide Opening By Carbon Nucleophilesmentioning

confidence: 99%

“…Carbon nucleophiles which do not readily trigger the rearrangement of epoxides include lithiated dithianes [295,304], lithiated sulfones [238], lithiated diarylphosphine oxides [240,305], lithium enolates [306], and allylic organolithium or organomagnesium compounds [298,[307][308][309][310] (Scheme 4.67). 105 Scheme 4.67.…”

Section: Epoxide Opening By Carbon Nucleophilesmentioning

confidence: 99%

Aliphatic Nucleophilic Substitutions: Problematic Electrophiles

Dörwald

2004

Side Reactions in Organic Synthesis

View full text Add to dashboard Cite

Nucleophilic substitutions at sp 3 -hybridized carbon are among the most useful synthetic transformations, and have been thoroughly investigated [1][2][3]. The success of these reactions depends mainly on the structures of the nucleophile and electrophile, their concentration, and on the solvent and reaction temperature chosen. The structure of the electrophile in nucleophilic substitutions is of critical importance, because many unwanted side reactions result from unexpected reactivity of the electrophile.In Scheme 4.1 the mechanisms of typical monomolecular (Sn1) and bimolecular (Sn2) nucleophilic substitutions at a neutral electrophile with an anionic nucleophile are sketched. Sn1 reactions usually occur when the electrophile is sterically

show abstract

“…The propynyl alcohol 2 was formed, from cyclohexene oxide 1, via a copper catalysed ring opening reaction with 4-pentenylmagnesium bromide. 12 Oxidation of the hydroxyl group and propargylation provided 2 in an overall yield of 42%. Exposure of 2, to dicobalt octacarbonyl, followed by an in situ dehydroxylation reaction led to cyclisation.…”

mentioning

confidence: 99%

The Synthesis of Bridged and Fused Ring Carbocycles Using a Novel Variation of an Intramolecular Nicholas Reaction

Tyrrell¹,

Skinner²,

Bashir³

2001

Synlett

View full text Add to dashboard Cite

A novel variation of an intramolecular Nicholas reaction is described that provides an efficient method for the synthesis of fused and bridged bicyclic compounds. The mechanism appears to involve an initial regioselective in situ double bond migration of a terminal alkene. The more stable disubstituted alkene then undergoes an intramolecular cyclisation reaction with a dicobalt hexacarbonyl stabilised cation. This transformation generates a second cation, which is subsequently quenched by a halide ion derived from the Lewis acid.Interest in the chemistry of dicobalt octacarbonyl has arisen from its uses in the Pauson-Khand reaction 1 the cyclotrimerisation of alkynes, 2 the Nicholas reaction 3 and other useful applications. 4 Our interest in the chemistry of dicobalt hexacarbonyl clusters stems from their use in the Nicholas reaction which is the reaction of a cobalt stabilised propynyl cation with a nucleophile.In general it is found that for both inter and intramolecular examples of the Nicholas reaction activated alkenyl derivatives are used to quench the dicobalt hexacarbonyl stabilised propynyl cation. Representative examples include O-silylenol ethers, 5 allyl silanes, 6 enamines 7 and aromatic compounds. 8Due to the instability of some of these derivatives, as well as the additional steps required to bring about their formation, we have instigated a series of studies aimed at investigating the synthetic utility of less functionally sensitive moieties and their use in intramolecular cyclisation reactions. To this aim we have recently shown that gem-dimethyl substituted double bonds are sufficiently activated to attack a Nicholas cation and effect a cyclisation reaction. 9Following on from an earlier observation 10 we have now been able to effect a range of cyclisation reactions using a simple pendant alkenyl moieties to quench the Nicholas cation. This communication describes the results obtained from these investigations into the synthesis of both fused and bridged ring carbocycles and serve to compliment the cyclisation reactions that we have previously revealed. 11In order to access both fused ring and bridged ring carbocycles cyclisation precursors were produced such that the propynyl alcohol moiety was either a or b to a pendant alkenyl group. Our initial study for the synthesis of the bicyclo[4:3:0] nonane framework is illustrated in (Scheme 1). The propynyl alcohol 2 was formed, from cyclohexene oxide 1, via a copper catalysed ring opening reaction with 4-pentenylmagnesium bromide. 12 Oxidation of the hydroxyl group and propargylation provided 2 in an overall yield of 42%. Exposure of 2, to dicobalt octacarbonyl, followed by an in situ dehydroxylation reaction led to cyclisation. Decomplexation of the dicobalt hexacarbonyl moiety with CAN provided, compound 3a, using TiCl 4 , or 3b, using TiBr 4 , in good overall yields. Scheme 1In order to gain access to bridged ring carbocyclic compounds cobalt clusters derived from propynyl alcohols, such as compound 4, were synthesised (Scheme 2) with the termina...

show abstract

Copper-catalysed reactions of allylic grignard reagents with epoxides.

Cited by 38 publications

References 10 publications

Intramolecular Cyclopropanation of Epichlorohydrin-Derived Unsaturated Chlorohydrins

Intramolecular Cyclopropanation of Epichlorohydrin-Derived Unsaturated Chlorohydrins

Aliphatic Nucleophilic Substitutions: Problematic Electrophiles

The Synthesis of Bridged and Fused Ring Carbocycles Using a Novel Variation of an Intramolecular Nicholas Reaction

Contact Info

Product

Resources

About