【摘要】 研究了Ni(Ⅱ)-手性(4S,4’S)-2,2’-(4,6-二苯并呋喃二基)双[4,5-二氢-4-苯基噁唑](DBFOX/Ph)金属配合物催化氰亚胺与N-(α,β-不饱和)酰基吡唑的不对称1,3-偶极环加成反应.该策略为制备包含四取代的一个或两个连续立体中心的手性5-3,5-二甲基吡唑酰基二氢吡唑环加成产物提供了一条简便可行的途径.研究结果表明,通过该反应可以高产率(97%)、高区域选择性(100%)和对映选择性(97.5%ee)地得到光学活性的环加成产物.在放大的克级反应中产物的收率和光学活性均可以很好地保持.此外,手性环加成产物可经过亲核和还原等5种反应生成含有不同取代基的手性二氢吡唑衍生物.更多还原

【Abstract】 The Ni(Ⅱ)-chiral(4S,4’S)-2,2’-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented. This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cycloadducts bearing one or two contiguous stereocenters in good yields(up to 97% yield) with high regioselectivities(100%)and enantioselectivities(up to 97.5% ee). Following that, chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process, additionally, toward five kinds of derivatization reactions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.更多还原