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In the Baylis–Hillman reaction of aldehydes with an α,β-unsaturated ketone, the chlorinated compound 1 was obtained as the major product using tributylphosphine as a Lewis base in the presence of titanium(IV) chloride, zirconium(IV) chloride or boron trichloride in dichloromethane at

The Baylis-Hillman reaction of aldehydes with alpha,beta-unsaturated ketones can be drastically affected by the reaction temperature and Lewis bases. When the reaction was carried out at -78 degrees C using catalytic amounts of quaternary ammonium salts (R4N+X-, X = Cl, Br, I) as Lewis bases, in the presence of titanium(IV) chloride, the chlorinated aldol adduct 1 was obtained as the major product. Quaternary ammonium bromides and iodides (R4N+X-, X = Br, I) have higher catalytic activity than corresponding chlorides (R4N+Cl-). Quaternary ammonium fluorides (R4N+F-) do not have activity at all. The amounts of Lewis acid and quaternary ammonium salts used affect the reaction rate and product. A plausible reaction mechanism is proposed. If the reaction was carried out at room temperature (about 20 degrees C) in the presence of titanium(IV) chloride and quaternary ammonium salts (R4N+X-, X = Cl, Br, I), the elimination product 3, derived from 1, was formed as the major product.

Chiral C 2 -symmetric 2,3-disubstituted aziridines and 2,6-disubstituted piperidines having a β-amino alcohol moiety have been successfully synthesized and their catalytic chiral induction properties have been examined in the asymmetric addition reactions of diethylzinc with arylaldehydes in hexane. When N -(2,2-diphenyl-2-hydroxyethyl)-( S , S )-2,3-bis(methoxymethyl)aziridine 11 was used as a catalytic chiral ligand, sec -alcohols having ( S )-configuration formed in high yields of 86–92% but low enantiomeric excesses (ee's) of 11–13%. However, when N -(2,2-diphenyl-2-hydroxyethyl)-( R , R )-2,6-disubstituted piperidine derivatives 16 and 20 were used as the chiral ligands under the same reaction conditions, the ee's of the corresponding sec -alcohols were 20–30 and 5–6%, respectively, along with the inversion of absolute configuration. A plausible mechanism for this inversion is proposed.

In the Baylis-Hillman reaction, we found that, when the reactions of arylaldehydes with methyl vinyl ketone were carried out at-20 degrees C using a catalytic amount of amine as a Lewis base in the presence of titanium(IV) chloride, the chlorinated compounds 1 could be obtained as the major product in very high yields for various arylaldehydes. In addition, acrylonitrile could undergo the same reaction to give the corresponding chlorinated product in moderate yield.

In the reaction of trans-2,4-disubstituted azetidine, trans-2,5-disubstituted pyrrolidine, or trans-2,6-disubstituted piperidine with diphenylthiophosphinic chloride or diphenylselenophosphinic chloride in acetonitrile in the presence of potassium carbonate at room temperature, an unexpected carbon dioxide insertion produced carbamic diphenylthiophosphinic or diphenylselenophosphinic anhydride in good yield. The same product could be also obtained when the reaction was carried out under carbon dioxide atmosphere using potassium hydroxide or triethylamine as a base. This is a very simple reaction process related to the fixation of carbon dioxide without a metal catalyst.

A series of chiral bidentate ligands having different ring sizes of cyclic amines have been synthesized. Their catalytic abilities on chiral inductions have been examined in the asymmetric cyclopropanation of styrene catalysed by copper(I) triflate.

The Baylis−Hillman reaction of aldehydes with α,β-unsaturated ketones can be drastically affected by the reaction temperature and Lewis bases. When the reaction was carried out at −78 °C using catalytic amounts of quaternary ammonium salts (R4N+X-, X = Cl, Br, I) as Lewis bases, in the presence of titanium(IV) chloride, the chlorinated aldol adduct 1 was obtained as the major product. Quaternary ammonium bromides and iodides (R4N+X-, X = Br, I) have higher catalytic activity than corresponding chlorides (R4N+Cl-). Quaternary ammonium fluorides (R4N+F-) do not have activity at all. The amounts of Lewis acid and quaternary ammonium salts used affect the reaction rate and product. A plausible reaction mechanism is proposed. If the reaction was carried out at room temperature (about 20 °C) in the presence of titanium(IV) chloride and quaternary ammonium salts (R4N+X-, X = Cl, Br, I), the elimination product 3, derived from 1, was formed as the major product.

In the Baylis–Hillman reaction of aldehydes with an α,β-unsaturated ketone, the chlorinated compound 1 was obtained as the major product using tributylphosphine as a Lewis base in the presence of titanium(IV) chloride, zirconium(IV) chloride or boron trichloride in dichloromethane at

In the baylis0hillman reaction, we found that, when the reactions of aryladehydes with methyl vinyl ketone were carried out at ←20℃ using a catalytic amount of amine as a lewis base in the presence of titanium(IV)chloride, the chlorinated compounds 1 could be obtained as the major product invery high yields for various arylaldehydes. In addition, acrylonitrile could undergo the same reaction to give the corresponding chlorinated product in moderate yield./*

In the reaction of trans-2,4-disubstituted azetidine, trans-2,5-disubstituted pyrrolidine, or trans-2,6-disubstituted piperidine with diphenylthiophosphinic chloride or diphenylselenophosphinic chloride in acetonitrile in the presence of potassium carbonate at room temperature, an unexpected carbon dioxide insertion produced carbamic diphenylthiophosphinic or diphenylselenophosphinic anhydride in good yield. The same product could be also obtained when the reaction was carried out under carbon dioxide atmosphere using potassium hydroxide or triethylamine as a base. This is a very simple reaction process related to the fixation of carbon dioxide without a metal catalyst.