13376-16-4Relevant articles and documents
Solvation and Steric Effects on Electrophilic Reactivity of Ethylenic Compounds. 1. Stereochemistry and Bromination of Congested Adamantylidenealkanes
Ruasse, Marie-Francoise,Motallebi, Shahrokh,Galland, Bernard,Lomas, John S.
, p. 2298 - 2303 (1990)
In order to evaluate the dependence of the steric effects of alkyl groups on the crowding of the double bond, bromination rate constants of adamantylidenealkanes 1, Ad=CRR' with R = H or Me and R'= H, Me, i-Pr, t-Bu, or neo-Pe, and similarly substituted isopropylidenealkanes 2, Me2C=CRR', are compared.Since the bromination rate of 1a (R = R'= H) is that expected by considering only the polar effect of two gem-isopropyls, the adamantyl group in 1, like the gem-methyls in 2, clearly does not exhibit anyl intrinsic steric effect.However, branched substituents R'slow thereaction of 1 twice as much as that of 2.This difference between the effects on 1 and 2 does not arise from differences in the stereoarrangement of R and R'since, according to MM2 calculations, they adopt exactyl the same conformation in both alkene series.Comparision of the bromination rates of 1 in methanol with those measured in acetic acid reveals that the solvent effect (kMeOH/kAcOH about 4) is markedly smaller than that (kMeOH/kAcOH = 25) on linear alkenes, which suggests that greater steric retardation in adamantylidenealkanes can be attributed to mechanistic changes: inhibition of nucleophilic solvent assistance in the ionization step and/or return resulting from a slow product-forming step.
Stereospecific Iron-Catalyzed Carbon(sp2)-Carbon(sp3) Cross-Coupling with Alkyllithium and Alkenyl Iodides
Lu, Xiao-Lin,Shannon, Mark,Peng, Xiao-Shui,Wong, Henry N. C.
supporting information, p. 2546 - 2549 (2019/03/26)
An efficient synthetic protocol involving iron-catalyzed cross-coupling reactions between organolithium compounds and alkenyl iodides as key coupling partners was achieved. More than 30 examples were obtained with moderate to good yields and high stereospecificity. Gram-scale and synthetic applications of this procedure are recorded herein to demonstrate its feasibility and potential utilization.
A novel and efficient method for the olefination of carbonyl compounds with Grignard reagents in the presence of diethyl phosphite
Wang, Tongqiang,Hu, Yuanyuan,Zhang, Songlin
supporting information; experimental part, p. 2312 - 2315 (2010/07/09)
The widely available carbonyl compounds react with Grignard reagents in the presence of diethyl phosphite to give the corresponding olefins in good to excellent yields: A range of conjugated dienes, terminal olefins, multisubstituted-alkenes and conjugated enynes could be readily obtained by the method in mild conditions.
