Some α,β-unsaturated esters bearing an imidazolidine chiral controller at the β-position were employed in the asymmetric cycloaddition to nitrile oxides. Regio- and diastereoselectivities were both poor when the chiral controller was a perhydropyrrolo[1,2-c]imidazol-3-yl auxiliary, while the reaction of the esters bearing a C2-symmetric imidazolidine chiral controller was exclusively regioselective or diastereoselective depending upon the nature of N-substituent. The transition state was briefly discussed.
一些在 β 位带有
咪唑烷手性控制剂的 α,β-不饱和酯被用于与腈氧化物的不对称环加成反应。当手性控制剂是全氢
吡咯并[1,2-c]
咪唑-3-基助剂时,区域选择性和非对映选择性都很差,而带有C2对称
咪唑烷手性控制剂的酯的反应完全是区域选择性或非对映选择性,具体取决于N-取代基的性质。简要讨论了过渡状态。