Aldol reactions Boron trichloride

Condensation Reactions. Boron trichloride converts ketones into (Z)-boron enolates at —95 °C in the presence of Diisopropyl-ethylamine. These enolates react with aldehydes with high syn diastereoselectivity (eq 2). A similar condensation of imines with carbonyl compounds also provides crossed aldols in reasonable yields. The reaction was extended to the asymmetric aldoi condensation of acetophenone imine and benzaldehyde by using isobornylamine as a chiral auxiliary (48% ee). ... 

Organoaluminum reagents, 202 1,1,1-Trifluoroacetone, 323 Trityllithium, 338 Zinc chloride, 349 Stereoselective aldol reactions With boron enolates Boron trichloride, 43 Chlorodimethoxyborane, 73 9-(Phenylseleno)-9-borabicyclo-[3.3.1]nonane, 245 With silyl enol ethers... 

Phenyliodine(III) bis(trifluoro-acetate), 241 Potassium hydride, 257 (3-Hydroxy aldehydes and ketones By aldol reactions Bis(2-pyridinethiolato)tin(II), 40 Boron trichloride, 43 Formaldehyde, 136... 

Alkenylaminoboranes (14), though not in the category of alkenyloxyboranes, also undergo aldol reactions with carbonyl compounds (Scheme 13). Pure alkenylaminoboranes can be isolated from the reaction of a ketimine, boron trichloride and triethylamine in dichloromethane. ... 

Aldol Reactions. - Seebach et al. have published a detailed study of the diasteroselective aldol reaction of boron enolates, generated from an ethyl ketone by treatment with boron trichloride or an alkoxydichloroborane in the presence of Hunig s base. The reaction was found to occur with ul topicity in selectivities from 90-99%... 

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