摘要
传统的(口片)呐偶合反应必须在无水有机溶剂条件下,由金属或金属化合物促进羰基化合物进行(口片)呐偶合反应.曾经报道过金属锌在强碱介质或弱酸介质中,促进羰基化合物进行水相(口片)呐偶合反应.本文报道一种简便、有效的水相(口片)呐偶合反应,它是在含有少量冠醚的稀氨水溶液中,使用锌粉促进醛基化合物进行水相(口片)呐偶合反应,其中加入少量的冠醚有助于提高反应的产率,(口片)呐醇产率由63%提高到84%.然而,(口片)呐偶合反应的产率受到羰基周围环境的立体位阻影响较大,在此条件下,锌粉能有效地促进芳香族醛类化合物进行水相(口片)呐偶合反应,得到的(口片)呐醇产率高,但非对映异构体选择性差,而脂肪族醛类化合物得到的(口片)呐醇产率较低,在同样的条件下,酮类化合物不能顺利进行(口片)呐偶合反应。
The conventional pinacol coupling of carbonyl compounds was carried out by using metals or metal compounds as mediators under condition of anhydrous organic solvents. Previously, it was reported that the pinacol coupling of carbonyl compounds was achieved by zinc under strong base or weak acid condition. Now, a convenient, efficient pinacol coupling of aldehydes mediated by zinc in good yields has been carried out in ammonia water in the presence of a little crown ether. Adding a small amount of crown ether was highly effective to enhance the yields of pinacol from 63% to 84%. Nevertheless, the yield of pinacol was also strongly affected by the steric environment surrounding the carbonyl group. The pinacol coupling of aromatic aldehydes has been achieved with high yields under such a condition. However, the diastereose- lectivities of pinacols were not satisfying. Unfortunately, the ketones and most aliphatic aldehydes appeared inert under the same reaction conditions.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2009年第7期1158-1160,共3页
Chinese Journal of Organic Chemistry
