4-Methyl-3-heptanone SAMP-hydrazone,

S)-(+)-4-Methyl-3-heptanone SAMP-hydrazone 1-Pyrrolidinamine, N-(l-ethyl-2-methyl pentyl idene)-2-(methoxymethyl)-, [S-[R, R -(Z)]i- (10) (69943-24-4) Propyl iodide Propane, 1-iodo- (8,9) (107-08-4)... 

Methyl-3-heptanone SAMP-hydrazone, (S)-(+)- 1-Pyrrol Id Inamine,... 

Reaction of 3-pentanone with the commercially available hydrazine (5)-l-amino-2-methoxymethylpyrrolidine (SAMP) affords the corresponding chiral hydrazone. Deprotonation with LDA followed by alkylation and hydrolysis furnishes (S)-4-methyl-3-heptanone in greater than 99% enantiomeric excess. Using the corresponding (R)-hydrazine (RAMP) provides (R)-4-methyl-3-heptanone. 

Figure 3.10 Natural product synthesis imploying SAMP-RAMP hydrazones 5-(+)-4-methyl-3-heptanone, the leaf cutting ant alarm pheromone [105] serricornin, the sex pheromone of the cigarette beetle [120] S,E-4,6-dimethyl-6-octen-3-one, the defense substance of daddy longlegs [120] (+)-eremophilenolide [120] and antibiotic X-14547A [121], Stereocenters formed by asymmetric alkylation are indicated by. ...

Alkylation of lithiated hydrazones forms the basis of an efficient method for the asymmetric alkylation of aldehydes and ketones, using the optically active hydrazines (5)-l-amino-2-(methoxymethyl)pyrroUdine (SAMP) 59 and its enantiomer (RAMP) as chiral auxiliaries. Deprotonation of the optically active hydra-zones, alkylation and removal of the chiral auxiliary under mild conditions (ozonol-ysis or acid hydrolysis of the A-methyl salt) gives the alkylated aldehyde or ketone with, generally, greater than 95% optical purity. This procedure has been exploited in the asymmetric synthesis of several natural products. Thus, (S)-4-methyl-3-heptanone, the principal alarm pheromone of the leaf-cutting ant Am texana, was prepared from 3-pentanone in very high optical purity as shown in Scheme 1.74. 

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