Stereocontrol in the EtAlCl(2)-induced cyclization of chiral gamma,delta-unsaturated methyl ketones to form cyclopentanones.
EtAlCl(2)-induced cyclization of chiral gamma,delta-unsaturated ketones 11c and 17b takes place mainly from the expected face. The selectivity is modest for 11c (60:40) in which the large substituent is a primary alkyl group and the medium substituent is a methyl group and excellent for 17b (93:7) in which the large substituent is a cyclohexyl group and the medium substituent is a methyl group. The cyclization of 17a is anomalous, suggesting that the phenyl group has more than a simple steric effect.
Snider
Barry B
BB
Department of Chemistry, MS 015, Brandeis University, Waltham, Massachusetts 02454-9110, USA. snider@brandeis.edu
Lobera
Mercedes
M
Marien
Tracy P
TP
D003500:Cyclization; D003517:Cyclopentanes / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D007659:Ketones / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000737:chemistry*
D003517:Cyclopentanes; D007202:Indicators and Reagents; D007659:Ketones; D009942:Organometallic Compounds; C007201:cyclopentanone; C481905:dichloroethylaluminum