Use of Enantiopure Alkoxyallenes in the Enantioselective Preparation of α-(Alkoxyalkyl)vinyl Ketones

All articles of this category Homochiral alkoxyallenes, easily prepared from propargylic bromide and a chiral alcohol (aminoalcohols or sugars) are transformed after deprotonation and reaction with an aldehyde to α-hydroxyallenic ethers. The diastereoselection, which largely depends on the chiral auxiliary and on the steric hindrance of the aldehyde is often in the range 50-85%. The acidic hydrolysis of these compounds happens without noticeable racemization providing chiral alcohols 1 with satisfactory enantiomeric excess.