Allylation of aromatic aldehydes

Diastereoselective allylation of aromatic aldehyde. Bulletin of the Chemical Society of Japan, 68, 1523. 

Mn. Manganese is also effective for mediating aqueous carbonyl ally-lations and pinacol-coupling reactions. Manganese offers a higher reactivity and complete chemoselectivity toward allylation of aromatic aldehydes.178... 

Allylation of aromatic aldehydes with allyl trimethylsilane catalyzed by chiral acyloxyborane gives good results. In contrast, the results are normally poor for aliphatic aldehydes.89 Costa et al.90 introduced another enantioselective allylation procedure aiming to overcome this problem. In the following example, the enantioselective allylation of aldehyde octanal was carried out using... 

S)-Prolinc-dcrivcd phosphoramides catalyse enantioselective allylation of aromatic aldehydes with allylic trichlorosilanes.90 Chiral a-aminoaldehydes have been allylated diastereoselectively with various reagents.91... 

Stereo specific generation and reactions of allylic alkali and alkaline earth metals have been reviewed121 and solvent-mediated allylation of carbonyl compounds with allylstannanes has been explored.122 Chiral phosphoramides derived from (5 )-proliiie have been used to catalyse asymmetric allylation of aromatic aldehydes by allylic trichlorosilanes.123... 

Several variations of this system were reported replacing, for instance, Ti(OPr-i)4 by Zr(OPr-/)4 or ZrCU, leading to a more reactive catalyst, particularly suitable for the allylation of aromatic aldehydes . The use of activators, such as /-PrSSiMe3, i-PrSBEt2, j-PrSAlEt2 or B(OMe)3, was reahzed for both systems. They are believed to accelerate the reaction by regenerating the or Zr catalysts. Finally, one of the more active cat-... 

Nano-tin is prepared by reduction of SnCL with isopropanol and irradiation under ay-ray source ( °Co) and has a particle size of 20-30 nm. Allylation of aromatic aldehydes in water are almost quantitative and reaction times are reduced from 8-24 hours for regular tin powder to 1.5-8 hours. Aliphatic aldehydes... 

Iseki et al. later improved the catalytic process and showed that chiral phos-phoramides 15,16, and 17, prepared from (S)-proHne, are suitable to catalyze the asymmetric allylation of aromatic aldehydes to give chiral homoallylic alcohols 34 with up to 88% ee (Scheme 13) [36,37]. The same group has also developed a chiral formamide 18 as a chiral Lewis base catalyst [38]. This catalyst is convenient for the allylation of aUphatic aldehydes with high enantioselectivity. A typical aromatic aldehyde, benzaldehyde, gives a low enantiomeric excess (Scheme 13). 

Barbier reactions. Allylation of aromatic aldehydes in 0.1 N ammonium chloride solution using a combination of Mg and an allyl bromide or iodide (but not ally chloride) has been demonstrated." Unfortunately, aliphatic aldehydes give complex mixtures. However, conjugate addition to enones can be achieved with mediation by Cul. 

Di-f-butyl tartrate and tin(II) catecholate, together with Cul and DBU, promote the allylation of aromatic aldehydes, producing homoallylic alcohols with high ee values. Diallyltin dibromide in the presence of the N-butyl-2-piperidinomethylpyrrolidine 38 also gives useful results. ... 

Nishida, M., Tozawa, T., Yamada, K. and Mukaiyama, T. (1996) Asymmetric allylation of aromatic aldehydes using chiral allylic tin reagents. Chemistry Letters, 25,1125-1126 Yamada, K., Tozawa, K., Nishida, M. and Mukaiyama, T. (1997) Asymmetric allylation of carbonyl compounds with tartrate-modified chiral allylic tin reagents. Bulletin of the Chemical Society of Japan, 70, 2301-2308. 

Wang, Z., Kisanga, P. and Verkade, J.G. (1999) P( PrNCH2CH2)3N an effective Lewis base promoter for the allylation of aromatic aldehydes with allyltrimethylsilane. The Journal of... 

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