摘要:
The site of Michael addition of beta-hetero atom substituted thiols (such as mercaptoethanol) to unsubstituted 2, 4-dienone and 2, 4, 6-trienones is at the terminal (omega) position. This site preference is transferred to the beta site when the addition is accomplished using Ti+4 complexation. These beta site addition products rapidly rearrange to the omega position on base treatment. (C) 1997 Elsevier Science Ltd.