有机催化不对称[3+3]环化合成新型光学活性稠合多环3,4-二氢吡喃并[4,3-b]吡喃-5-(2H)-酮（英文）

Asymmetric Synthesis of Novel Fused Polycyclic 3,4-Dihydropyrano[4,3-b]pyran-5(2H)-ones via an Organocatalyzed Formal [3+3] Annulation

发展了一种手性双功能方酰胺催化的4-羟基-2(H)-吡喃并[2',3':4,5]吡喃并[2,3-c]吡唑-2,5(7H)-二酮与(E)-2-硝基烯丙基醋酸酯之间的对映选择[3+3]环化反应,为立体选择构筑稠合多环3,4-二氢吡喃并[4,3-b]吡喃-5-(2H)-酮骨架提供了途径.在衍生自(1R,2R)-1,2-二苯基乙-1,2-二胺的手性双功能方酰胺的催化下,以中等至较高产率、高的反式选择性和中等至优秀的对映选择性得到了一系列具有两个连续手性中心的新型稠合多环3,4-二氢吡喃并[4,3-b]吡喃-5-(2H)-酮衍生物.

A chiral bifunctional squaramide catalyzed enantioselective formal[3+3] annulation of 4-hydroxy-2H-pyrano[2',3':4,5]pyrano[2,3-c]pyrazole-2,5(7H)-diones and (E)-2-nitroallyl acetates has been developed,which provides an efficient approach to stereocontrolled construction of fused polycyclic 3,4-dihydropyrano[4,3-b]pyran-5(2H)-one scaffold.Under the catalysis of a bifunctional squaramide derived from (1R,2R)-1,2-diphenylethane-1,2-diamine,a wide range of novel fused polycyclic 3,4-dihydropyrano[4,3-b]pyran-5(2H)-one derivatives with two adjacent stereogenic centers are obtained in acceptable yields with high anti-selectivity and moderate to excellent enantioselectivity.Representative transformation of the annulation product to other synthetic valuable compound is achieved without any loss of stereochemical integrity.