1005347-89-6

Upstream product

• 109-65-9 1-bromo-butane 
• 123-11-5 4-methoxy-benzaldehyde 
• 110-62-3 pentanal 
• 82303-13-7 (4-methoxyphenyl)zinc(II) bromide 
• 104-92-7 1-bromo-4-methoxy-benzene 
• 109-72-8 n-butyllithium 

Relevant academic research and scientific papers

Asymmetrie lithiation-substitution of amines involving rearrangement of borates

Asymmetric lithiation of substituted benzylamines, N-Boc-pyrrolidine, or N-Boc-indoline using Beak's methodology was followed by electrophilic quench with trialkylboranes. The resulting borate intermediates rearrange with concomitant C-N bond breakage to give, after oxidation, chiral secondary alcohols with high enantioselectivity.

Catalytic asymmetric addition of alkyllithium reagents to aromatic aldehydes

Herein, we report the first efficient catalytic system for the asymmetric alkylation of aldehydes with organolithium reagents in the presence of titanium(IV) isopropoxide. A variety of alkyllithium reagents can be added to aromatic aldehydes in good yields with high enantioselectivities in a simple one-pot procedure under mild conditions. Herein, we report the first efficient catalytic system for the asymmetric alkylation ofaldehydes with organolithium reagents in the presence of titanium(IV) isopropoxide. A variety of alkyllithium reagents can be added to aromatic aldehydes in good yields with high enantioselectivities in a simple one-pot procedure under mild conditions. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catalytic enantioselective addition of MeMgBr and other Grignard reagents to aldehydes

Herein, we report an efficient catalyst for the challenging enantioselective addition of MeMgBr to aldehydes. Unprecedented yields and enantioselectivities are achieved in the reaction with a broad range of aldehydes. Moreover, a variety of Grignard reagents can be also added to aromatic and aliphatic aldehydes in good yields and enantioselectivities in a simple one-pot procedure under mild conditions.

On the scope of trimethylaluminium-promoted 1,2-additions of ArZnX reagents to aldehydes

A practical asymmetric 1, 2 addition of functionalised arylzinc hal ides to aromatic and aliphatic aldehydes is described by the use of amino alcohol catalysis in the presence of AlMe3. The process is simple to carry out, uses only commercially available reagents/ligands and provides moderate to good (80-96% ee) enantioselectivities for a wide range of substrates. Either commercial ArZnX reagents or those prepared in situ from low cost aryl bromides can be used. In the latter case electrophilic functional groups are tolerated (CO2Et, CN). The reaction relies on rapid exchange between ArZnX and AlMe3 to generate mixed organometallic species that lead to the formation of a key intermediate that is distinctly different from the classic "anti" transition states of Noyori. NMR monitoring and related experments have been used to probe the validity of the proposed selective transition state.

Ti-TADDOLate-Catalyzed, Highly Enantioselective Addition of Alkyl- and Aryl-Titanium Derivatives to Aldehydes

Toluene-ether or toluene-hexane solutions of aryl and alkyl triisopropoxy titanium reagents (free of Li, Mg, or Zn salts) are prepared from the corresponding Li or Grignard reagents and ClTi(OiPr)3, with careful removal of salts (centrifugation of LiCl or of dioxane*MgX2, and addition of 12-crown-4).The solutions of the organotitanium compounds are combined with one equiv. of an aldehyde and 0.2 equiv. of (R,R)-diisopropoxy-(α,α,α',α'-tetraphenyl-2,2-dimethyl-1,3-dioxolane-4,5-dimethanolato) titanium (Ti-TADDOLate 3) at dry-ice temperature.Warming up to room temperature leads to nucleophilic addition to the (Si)-face of the aldehydes with enantioselectivities as high as 99.5 : 0.5 (products 4-33 in Scheme 4).Functional groups or protecting groups and branching in the Ti-R group and in the aldehyde must be remote from the reacting centers.Aryl groups can be added to aldehydes by this method. - In contrast to all the enantioselective R2Zn additions to aldehydes, in which only one R-group is actually transferred, a twice as economic use is made of the originally employed R-metal reagent in the method described here. - A procedure for multigram preparation of the spiro-Ti-TADDOLate (2) employed for the in situ generation of catalyst (3) is described, and details of the determination of enantiomer ratios (er) by GC and NMR methods are given (Tab. 2, 3).The mechanistic interpretation of Ti-TADDOLate-mediated nucleophilic additions as derived previously (ref.4c) is also compatible with this monometallic variant of the method.