Synthesis of 2H-Chromenes via Hydrazine-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis
Synthesis of 2H-Chromenes via Hydrazine-Catalyzed Ring-Closing Carbonyl-Olefin Metathesis
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DOI：
10.1021/acscatal.9b03656
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发表时间：
2019-10-01
期刊：
影响因子：
12.9
通讯作者：
Lambert, Tristan H.
中科院分区：
文献类型：
--
作者：
Zhang, Yunfei;Jermaks, Janis;Lambert, Tristan H.
本文报道了O-烯丙基水杨醛催化闭环羰基-烯烃复分解反应（RCCOM）生成2 H-色烯的反应。该方法利用[2.2.1]-双环肼催化剂并通过[3 + 2]/逆-[3 + 2]复分解歧管操作。烯丙基取代模式的性质被发现是至关重要的，具有空间要求的基团如金刚烷基或二亚乙基提供最佳结果。衬底范围的调查显示沿着与DFT计算支持的机制的讨论。空间压力所产生的顺戊烷最小化的二亚乙基部分提出，以促进环逆转。
The catalytic ring-closing carbonyl-olefin metathesis (RCCOM) of O-allyl salicylaldehydes to form 2H-chromenes is described. The method utilizes a [2.2.1]-bicyclic hydrazine catalyst and operates via a [3 + 2]/retro-[3 + 2] metathesis manifold. The nature of the allyl substitution pattern was found to be crucial, with sterically demanding groups such as adamantylidene or diethylidene offering optimal outcomes. A survey of substrate scope is shown along with a discussion of mechanism supported by DFT calculations. Steric pressure arising from syn-pentane minimization of the diethylidene moiety is proposed to facilitate cycloreversion.