A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3•HBArF4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields
通过邻羟基芳族醛亚胺和a内酯的多米诺反应,已经实现了对3,4-二氨基苯并二氢吡喃-2-酮的高度对映选择性的合成。值得注意的是,通过使用胍2a获得了顺式产物作为主要产物,而反式产物是双胍盐3•HBAr F 4的主要产物。在两种情况下,以高收率(高达99%),出色的对映选择性(高达99%ee)和非对映选择性(高达> 99:1顺式:反式和98:2 )获得了各种取代的3,4-二氢香豆素。反式:顺式,分别)在温和的反应条件下。
Abnormal effect of hydroxyl on the longest wavelength maximum in ultraviolet absorption spectra for bis-aryl Schiff bases
作者:Chao-Tun Cao、Wei Zhou、Chenzhong Cao
DOI:10.1002/poc.3672
日期:2017.10
4‐HOArCH=NArY and XArCH=NArOH‐4′, and the second set consists of 2‐HOArCH=NArY and XArCH=NArOH‐2′. Their ultravioletabsorptionspectra were measured and investigated. A very interesting phenomenon was observed by analyzing their wave number νmax (cm−1) of longest wavelength maximum λmax (nm) of ultraviolet. Compared with the change regularity of the νmax of XArCH=NArY (where the X and Y excluded OH), the