Ni-DBFOX/Ph催化N-α,β-不饱和酰基吡唑与C,N-二芳基硝酮的不对称1,3-偶极环加成反应

Asymmetric 1,3-Dipolar Cycloaddition Reaction of C,N-Diarylnitrone with N-α,β-Unsaturated Acylpyrazoles Catalyzed by Ni-DBFOX/Ph

报道了(R,R)-4,6-二苯并呋喃二基-2,2'-双-4-苯基噁唑啉镍(Ni-DBFOX)型手性催化剂催化N-α,β-不饱和酰基吡唑与C,N-二芳基硝酮的不对称1,3-偶极环加成反应.研究结果表明,在10%催化剂存在下,反应的区域选择性为95∶5,endo/exo选择性为99∶1,ee值达到90%以上.对烯烃、硝酮结构、金属盐种类以及催化剂用量对反应的立体选择性影响进行了讨论.

Using（R,R）-4,6-dibenzofurandiyl-2,2＇-bis（4-phenyloxazoline）-Ni（Ni-DBFOX） as the catalyst, asymmetric catalytic 3-dipolar cycloaddition reactions between N-α,β-unsaturated acylpyrazoles and C,N-diarylnitrone have been developed with〉 95% regioselectivity and an endo/exo ratio of 99∶1 with 90% ee of the endo-diastereomer. Influence of olefins, nitrone structure, metal type and amount of catalyst on the reaction stereoselectivity was also carefully discussed.