3- acroleins, hydrolysis salts

Another application of this method is the stereoselective addition of (7 )-2-hydroxy-l,2,2-triphenylethyl acetate, via the lithium enolate, to propenal (acrolein) which affords mainly the ester 13 (d.r. 92 8). When the acid, obtained in the subsequent alkaline hydrolysis, is converted into the ammonium salt derived from (.S)-l -phenylethylaminc, and the salt recrystallized once, then the amine liberated (/f)-3-hydroxy-4-pentenoic acid is obtained in 41 % yield [relative to the (/ )-acetate] and >99.8% ee82. 

Aminodeoxy sugars are biochemically interesting due to their efficiency as enzyme inhibitors as well as their potential anti-HIV activity. Double deprotonation of 153 and subsequent treatment with acrolein affords 164 as the major diastereomer (92 8). Alkaline hydrolysis of this crude mixture provides (7 )-3-hydroxy-4-pentenoic acid (165) with 83.5% ee. This is easily enhanced by resolution via the (5)-l-phenethylammonium salt, so that 165 can in fact be obtained with 99% ee. lodolactonization of 165 generates the second stereogenic center and provides the furanone skeleton 166, isolated with 97.8% de. Depending on the sequence of transformations chosen, 166 can be converted either to methyl (3i ,47 )-5-amino-2,5-... 

Fluoromalonaldehyde (25), which exists in solution as the enol form Z configuration), has been condensed with heterocyclic JV -alkylinunonium salts to give y-fluoropentamethinecyanine dyes (see Scheme 23). Synthesis of the aldehyde (Scheme 22) involves hydrolysis of 2-fluoro-3-dimethylamino-acrolein, the product of Vilsmeier formylation of sodium fluoroacetate. - ... 

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