Nayak Kalinga H, Jijin Robert K, Babu Beneesh P
Department of Chemistry, National Institute of Technology Karnataka Surathkal Mangalore 575025 India
RSC Adv. 2025 Jul 10;15(30):24137-24141. doi: 10.1039/d5ra03561a.
Herein, we report an interesting [3 + 2] annulation/ring-opening cascade reaction between hydrazones and exocyclic dienones an aerobic, copper(ii) catalysis to synthesize 5-(pyrazol-4-yl) pentanoic acid and 4-(pyrazol-4-yl) butanoic acid derivatives. The annulation first affords a spiro pyrazoline with unprecedented regiochemistry, followed by a cascade nucleophilic ring opening by water to yield pyrazolyl pentanoic and butanoic acid derivatives in good yield. Broad substrate scope, inexpensive and green catalyst and oxidant, and relatively mild reaction conditions enhance the versatility of this protocol.
在此，我们报道了一种有趣的腙与环外二烯酮之间的[3 + 2]环化/开环级联反应，该反应采用需氧的铜（II）催化来合成5-（吡唑-4-基）戊酸和4-（吡唑-4-基）丁酸衍生物。环化首先以前所未有的区域化学方式得到一个螺吡唑啉，随后通过水进行级联亲核开环，以良好的产率生成吡唑基戊酸和丁酸衍生物。广泛的底物范围、廉价且绿色的催化剂和氧化剂以及相对温和的反应条件增强了该方法的通用性。
