Synthesis of optically active (+)-2-benzyl-, (+)-2-octyl-, and (+)-2-tetradec-5′-enylcyclobutanones via metallated chiral imines or hydrazones
作者:Damien Hazelard、Antoine Fadel
DOI:10.1016/j.tetasy.2005.04.012
日期:2005.6
A practical asymmetric synthesis of (R)-2-benzyl-, (S)-2-octyl-, and (S)-2-tetradec-5 -enylcyclobutanones was investigated using enantiopure (S)-alpha-methylbenzylamine, (R)-methoxyinethylbenzylamine, or hydrazine (RAMP). These amines were treated with cyclobutanone to afford the corresponding imines or hydrazones, respectively. Metallation of these imine derivatives followed by alkylation with n-octylbromide, benzylbromide, or tetradec-5-enylbromide gave, after hydrolysis, (S)-2-octylcyclobutanone and for the first time optically active (R)-2-benzylcyclobutanone and (S)-2-tetradec-5'-enylcyclobutanone (TECB) with 67-87% ee. The absolute configuration was also established. (c) 2005 Elsevier Ltd. All rights reserved.