Organometallics addition, imines

The synthesis of enantiopure amino-functionalized compounds such as a- and (3-amino acids or nonfunctionalized amines can be envisaged by the use of aldehydes, ketones, a- or (3-keto acids, or derivatives thereof as substrates for imine formation followed by, for example, diastereoselective Strecker reactions, reductions, or organometallic addition reactions. In the literature, diastereoselective syntheses based on a large variety of chiral auxiliaries, such as a-arylethylamines,4... 

Nucleophilic Addition to Imines and Mine Derivatives 1.12.8 ORGANOMETALLIC ADDITIONS TO OXIMES AND OXIME ETHERS... 

A base-induced ring-opening imine isomerization/diastereoselective organometallic addition sequence on 4-substituted-2-perfluoroalkyl-l,3-oxazolidines 205 was developed for the asymmetric synthesis of perfluoroalkyl amino alcohols 207 via intermediates 206. Chiral compounds were obtained in good yields and high diastereoselectivity <04OL641>. 

A very good stereoselectivity is manifested in the organometallic addition to imines when they are derived from chiral amines such as the SAMP/RAMP block and r af/jro-2-amino-1,2-diphenylethanol. ... 

The addition of copper-zinc organometallics to imines is sluggish. However, benzylic zinc halides possess sufficient reactivity and add directly to in situ generated imines. The secondary amine 514 was obtained from the benzylic zinc reagent 515 in 60% yield and 70% de (Scheme 2-148). ... 

Reaction of Nitriles with Organometallic Reagents Grignard reagents add to a nitrile to give an intermediate imine anion that is hydrolyzed by addition of water to yield a ketone. 

The addition of organometallic reagents to the C —N double bond of imines 1 provides an attractive route to amines 21 2. However, due to the poor electrophilici ty of imines, this method is often plagued by competitive reactions ... 

Addition of Grignard and organolithium reagents to imines 2. derived from enantiomerically pure (S)-valinol (1), provides a-substituted phenethylamines 3 in moderate to good yield and excellent diastereoselectivity (in each case only one diastereomer can be detected by NMR)15. By appropriate selection of imine and organometallic reagent both diastereomeric amines are accessible (see also refs 16 and 17). 

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