Indium-mediated asymmetric Barbier-type allylation of aldimines in alcoholic solvents: synthesis of optically active homoallylic amines.
[reaction: see text] Chiral aldimines derived from phenylglycinol were diastereoselectively allylated with indium powder/allyl bromide in alcoholic solvents. Both aliphatic and aromatic aldimines provided good yield of the desired products with high diastereoselectivity. A racemization-free protocol for removal of the phenylglycinol auxiliary was also developed. The stereochemical assignment of the homoallylic amine was made by NMR spectroscopy and a transition state model was proposed to explain the selectivity.
Vilaivan
Tirayut
T
Organic Synthesis Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand. vtirayut@chula.ac.th
Winotapan
Chutima
C
Banphavichit
Vorawit
V
Shinada
Tetsuro
T
Ohfune
Yasufumi
Y