1027790-97-1

Upstream product

• 591-87-7 Allyl acetate 
• 60211-57-6 3,5-dichlorobenzyl alcohol 
• 10203-08-4 3,5-dichlorobenzaldehyde 
• 107-37-9 allyltrichlorosilane 
• 24850-33-7 allyltributylstanane 

Relevant academic research and scientific papers

Enantioselective iridium-catalyzed carbonyl allylation from the alcohol or aldehyde oxidation level using allyl acetate as an allyl metal surrogate

Protocols for highly enantioselective carbonyl allylation from the alcohol or aldehyde oxidation level are described based upon transfer hydrogenative C-C coupling. Exposure of allyl acetate to benzylic alcohols 1a-i in the presence of an iridium catalyst derived from [IrCl(cod)]2 and (R)-BINAP delivers products of C-allylation 2a-i. Employing isopropanol as terminal reductant, exposure of allyl acetate to aryl aldehydes 3a-i in the presence of an iridium catalyst derived from [IrCl(cod)]2 and (-)-TMBTP delivers identical products of C-allylation 2a-i. In all cases examined, exception levels of enantioselectivity are observed. Thus, enantioselective carbonyl allylation is achieved from the alcohol or aldehyde oxidation level in the absence of any preformed allylmetal reagents. These studies define a departure from preformed organometallic reagents in carbonyl additions that transcend the boundaries of oxidation level. Copyright

Bispalladacycle Catalyzed Nucleophilic Enantioselective Allylation of Aldehydes by Allylstannanes

Enantiopure homoallylic secondary alcohols are very important synthetic building due to the versatility of the hydroxyl and olefin moieties. A key strategy to prepare them is by nucleophilic allylation of aldehydes. A large number of catalyst concepts emerged that allow for high enantioselectivity. Still, in many target-oriented syntheses of complex structures stoichiometric methods are preferred over catalytic ones. The need for high catalyst loadings and long reaction times, plus unsatisfying reproducibility and substrate scopes are reasons for that. In the present study we report the first palladium catalysts capable of controlling asymmetric nucleophilic allylations of aldehydes with allyltributyltin. TONs up to 620 were achieved, which is significantly higher than for any other reported catalyst. The method is also tolerating electronically and sterically unfavorable substrates. We show that a transmetallation occurs, favoring an η1-allyl coordination mode with the bispalladacycles. In contrast, for the corresponding monopalladacycle an unproductive η3 coordination is dominant.

Synthesis of axially chiral C10-BridgePHOS oxides and their use as organocatalysts in enantioselective allylations of aldehydes

A series of C10-BridgePHOS oxides possessing different substituted groups on the diphenyl phosphine system were synthesized and tested as organocatalysts in the allylation of aldehydes with allyltrichlorosilane, providing chiral homoallylic alc

Enantioselective iridium-catalyzed carbonyl allylation from the alcohol or aldehyde oxidation level via transfer hydrogenative coupling of allyl acetate: Departure from chirally modified allyl metal reagents in carbonyl addition

Under the conditions of transfer hydrogenation employing an iridium catalyst generated in situ from [Ir(COd)Cl]2, chiral phosphine ligand (R)-BINAP or (R)-Cl,MeO-BIPHEP, and m-nitrobenzoic acid, allyl acetate couples to allylic alcohols 1a-c, aliphatic alcohols 1d-1, and benzylic alcohols 1m-u to furnish products of carbonyl allylation 3a-u with exceptional levels of asymmetric induction. The very same set of optically enriched carbonyl allylation products 3a-u are accessible from enals 2a-c, aliphatic aldehydes 2d-1, and aryl aldehydes 2m-u, using iridium catalysts ligated by (-)-TMBTP or (R)-Cl,MeO-BIPHEP under identical conditions, but employing isopropanol as a hydrogen donor. A catalytically active cyclometallated complex V, which arises upon ortho-C-H insertion of iridium onto m-nitrobenzoic acid, was characterized by single-crystal X-ray diffraction. The results of isotopic labeling are consistent with intervention of symmetric iridium π-allyl intermediates or rapid interconversion of σ-allyl haptomers through the agency of a symmetric π-allyl. Competition experiments demonstrate rapid and reversible hydrogenation-dehydrogenation of the carbonyl partner in advance of C-C coupling. However, the coupling products, which are homoallylic alcohols, experience very little erosion of optical purity by way of redox equilibration under the coupling conditions, although isopropanol, a secondary alcohol, may serve as terminal reductant. A plausible catalytic mechanism accounting for these observations is proposed, along with a stereochemical model that accounts for the observed sense of absolute stereoinduction. This protocol for asymmetric carbonyl allylation transcends the barriers imposed by oxidation level and the use of preformed allyl metal reagents.