On the Regioselectivity of the Intramolecular [2 + 2]-Photocycloaddition of Alk-3-enyl Tetronates
作者:Roland Weixler、Jörg P. Hehn、Thorsten Bach
DOI:10.1021/jo201066d
日期:2011.8.5
The simple diastereoselectivity and the regioselectivity of the [2 + 2]-photocycloaddition of alk-3-enyl tetronates were studied, depending on the nature of the substituent R in the α-position. Fourteen tetronates were synthesized and their intramolecular photocycloaddition reactions performed. If R was an alkoxycarbonyl group and if the olefin, which underwent the intramolecular addition, was sterically
根据α位上取代基R的性质,研究了烷-3-烯基四价酸酯的[2 + 2]-光环加成反应的简单非对映选择性和区域选择性。合成了十四个四价酸盐,并进行了其分子内的光环加成反应。如果R是烷氧羰基并且分子内加成的烯烃在空间上是拥塞的,则交叉的光产物占优势,并且形成的收率在35%至65%之间。在所有其他情况下,获得的纯光产物作为主要反应产物,产率为39%至84%。通过一维和二维NMR实验对光化学产物的结构进行了彻底研究。在所有情况下,非对映选择性都非常好,并且仅形成了一个非对映异构体。