Acrylamides derived from 3,5-dimethyl-1H-pyrazole are employed in the asymmetric [3+2] cycloaddition with the allenoate, tert-butyl buta-2,3-dienoate, for the first time. d-Threonine-l-tert-leucine-based bifucntional phosphines are effective catalysts for the above reactions, affording regiospecific [3+2]-annulation products in excellent yields and with moderate enantioselectivities.
来源于3,
5-二甲基-1H-
吡唑的
丙烯酰胺首次用于与全烯酸酯(即叔丁基
丁烯-2,3-二酸酯)进行不对称[3+2]环加成反应。基于d-脯
氨酸-1-叔亮
氨酸的双功能膦催化剂对上述反应有效,能够生成具有区域选择性的[3+2]环化产物,收率优异且具有适度的对映选择性。