136984-21-9

Upstream product

• 109-72-8 n-butyllithium 
• 93-53-8 (R)-2-phenylpropanal 
• 34713-70-7 2-Phenylpropanal 
• 1119-90-0 di-n-butylzinc 
• 693-03-8 n-butyl magnesium bromide 

Relevant academic research and scientific papers

Simple deprotection of acetal type protecting groups under neutral conditions

Heating acetals with ethylene glycol causes the deprotection of acetal type protecting groups. When acetals such as MOM ethers, MEM ethers, and THP ethers were heated in ethylene glycol or propylene glycol, solvolysis proceeded smoothly to produce alcohols in excellent yield. This reaction is a very promising method for chemoselective deprotection of acetal type protecting groups.

Solvent and temperature effects on diastereofacial selectivity: Amines as co-solvents in n-butyllithium addition to α-chiral aldehydes

Temperature-dependent selectivity in nucleophilic additions to α-chiral aldehydes is affected by solvent mixtures. In this context, we investigated the effect on diastereoselectivity of tertiary amines as co-solvents. Addition of 5 mol% of an amine to hexane strongly influences the anti/syn ratio in the additions of nBuLi to 2-phenylpropanal and to (2S)-2-[(tertbutyl)dimethylsilyloxy]-2-propanal. In these hexane/amine mixtures as reaction solvents, we observed diastereoselectivities higher than those obtained in hexane. In the corresponding Eyring plots of ln(anti/syn) against the reciprocal temperature, we observed inversion temperatures (Tinv), these generally occurring at higher temperatures in the hexane/amine mixtures than in pure hexane. The presence of the inversion temperatures confirms that these tertiary amines take part in the solvation of the starting aldehyde, thus contributing to a solvent effect on facial selectivity. In some cases, the differential entropy of activation is the predominant factor in differentiating the diastereoselectivity among these hexane/amine mixtures. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

Asymmetric Synthesis of Optically Active Alcohols with Two Chiral Centres from a Racemic Aldehyde by the Selective Addition of Dialkylzinc Reagents Using Chiral Catalysts

Optically active alcohols with two chiral centres have been obtained in good to high e.e.s (enantiomeric excesses) from racemic 2-phenylpropanal 1 by diastereo- and enantio-selective addition of dialkylzinc reagents using (1S,2R)-(-)-N,N-dibutylnorephedrine (DBNE) and (S)-(+)-diphenyl(1-methyl-pyrrolidin-2-yl)methanol (DPMPM) as chiral catalysts.It was found that in the presence of (1S,2R)-(-)-DBNE, dialkylzinc selectively attacked racemic 1 from the Si-face of the aldehyde 1 regardless of the configuaration of 1 and that (S)-1 reacted faster with dialkylzinc than did (R)-1.

Asymmetric Synthesis of Alcohols with Two Chiral Centres from a Racemic Aldehyde by the Selective Addition of Dialkylzinc Reagents using (1S,2R)-(-)-N,N-Dibutylnorephedrine and (S)-(+)-Diphenyl-(1-methylpyrrolidin-2-yl)methanol as Chiral Catalysts

Optically active alcohols with two chiral centers were obtained in up to 93percent enantiomeric excess by the selective addition of dialkylzinc reagents to the racemic aldehyde, 2-phenylpropanal, using the title compounds as chiral catalysts.