Allyl Grignard reaction with

An allylaluminum species, which was generated by the reaction of allyl Grignard reagent with diisobutylaluminum chloride, was found to react with terminal alkynes in... 

Through known methodology, uridine was transformed into the aldehyde 88 (20) (Figure 14). Grignard reaction with allyl magnesium chloride gave a 7 1 mixture of C-5 Isomers and 90, with the crystalline C-5 (R) Isomer being preponderant. 

The use of the o-diphenylphosphanylbenzoyl leaving group in copper-catalysed allylic substitution reactions with a Grignard reagent has been studied extensively.7 ( ) High SN2 regiospecificity (>95%) and complete stereospecificity are observed at room temperature when the solvent is a dichloromethane - diethyl ethyl mixture. 

Linstrumelle, G. Lome, R. Dang, H. P. Cu-Catalysed reactions of allylic Grignard reagents with epoxides. Tetrahedron Lett. 1978, 4069-4072. 

Palladium-catalyzed allylation reactions proceed with net retention of configuration that is the result of two inversions.118-120 132-135 Grignard reactions with nickel or copper catalysis proceed with net inversion.128 136-138... 

Addition of 10% Cul to the reaction of allylic Grignard reagents with epoxides exerts a marked efiect on the regioselectivity. The catalyst also increases the rate of reaction. The a-products are also the main products when sufficient Cul is added to form the stoichiometric dialkyl cuprate of the Grignard reagent, but yields are lower than in the copper-catalyzed reaction. ... 

Allylic halides couple effectively with vinyltin reagents to provide the corresponding 1,4-dienes in high yields.2 Like nickel- and palladium-catalyzed Grignard reactions with allylic ethers, this reaction also proceeds with net inversion of configuration at the allylic center. Similarly, vinyl epoxides react... 

The unsaturated cationic titanium allyl compound [Gp 2Ti(allyl)]+BPh4- is prepared by oxidation of the titanium(m) allyl complex Cp 2Ti(allyl) with a ferrocenium cation. Nucleophilic addition to the cationic unit proceeds regioselectively to the central allylic position. Reaction with benzyl Grignard or the enolate of propiophe-none affords the corresponding titanacyclobutane complexes (Scheme 513).1305... 

The pyrrolinyl- (6-11) and pyrrolyl-substituted (12-13) eudistomin skeletons were first prepared by Rinehart from 1-cyano-P-carboline (145), which can be obtained from the corresponding acid (28). Grignard reaction with appropriately protected 3-bromopropanal (Scheme 4) provided the necessary carbons with appropriate oxidation level for cyclization to either of these ring systems. The pyrrolyl-substituted eudistomins then result upon hydrolysis of the imine and acetal functions with concomitant cyclization in the presence of ammonia. The pyrrolinyl-eudistomins require reduction of the imine to the amine followed by acetal hydrolysis and simultaneous ring closure to isomer 147. Reduction of the imine 147 followed by allylic oxidation with sodium hypochlorite isomerizes 147 to the pyrrolinyl-eudistomin skeleton (149). 

Other effective catalysts for similar reactions include RjP-ligated nickel and palladium derivatives. Chiral diamines mediate Grignard reactions with aldehydes. Two different tactics for the allylation of aldehydes with allylsilanes and allyl-... 

The reaction of allylic Grignard reagents with aldehydes to produce allylic carbinols does not always proceed smoothly. In the reaction of 3,4-methylene dioxybenzaldehyde with allyl alcohol (1.5-3.0 moles) at ambient temperature... 

Asymmetric methylation. The reaction of an allylic Grignard reagent with the... 

If reaction does not occur when a little allyl bromide is first introduced, further addition must be discontinued until the reaction has commenced. Remove 2-3 ml. of the Grignard solution with a dropper pipette, add about 0-5 ml. of allyl bromide and warm gently to start the reaction after this has reacted well, add the solution to the main portion of the Grignard reagent. 

Pyrroles do not react with alkyl halides in a simple fashion polyalkylated products are obtained from reaction with methyl iodide at elevated temperatures and also from the more reactive allyl and benzyl halides under milder conditions in the presence of weak bases. Alkylation of pyrrole Grignard reagents gives mainly 2-alkylated pyrroles whereas N-alkylated pyrroles are obtained by alkylation of pyrrole alkali-metal salts in ionizing solvents. 

The reactions of 2-propenyltitanium reagents with chiral aldehydes (0) or ketones ( and ) usually exhibit enhanced induced diastereoselectivities compared to allyl Grignard reagents. This enhanced diastereoselection is mainly attributed to the greater bulk and lower reactivity of the reagent. Some examples are collected ( )52. 

Treatment of (—)-(S)-276 with allyl Grignard reagents gives optically active allylic sulphoxides 288. This reaction, however, involves an allylic rearrangement via transition state 289 as evidenced by Mislow and his collaborators362 (equation 160). 

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