Allenes are the simplest class of cumulenes, possessing unique physical and chemical properties. These structural units are widely used as valuable synthetic intermediates in organic synthesis, as well as the key skeletons of many natural products, biologically active molecules, and pharmaceutical compounds. In recent decades, the development of synthetic methodologies for the synthesis of allenes by direct transformation of propargylic alcohols has attracted considerable attention among organic chemistry researchers. In this review, we focus on recent advances in the direct transformation of propargylic alcohols to allenes. These transformations can be divided into four categories according to their reaction types: (1) reactions with transition metal catalysis; (2) reactions involving carbocation intermediates; (3) reactions that are metal hydride (base)-mediated; and (4) reactions involving oxa-propargylic intermediates.

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炔丙醇直接转化为丙二烯的新进展

艾伦烯是最简单的枯草烯类，具有独特的物理和化学性质。这些结构单元被广泛用作有机合成中有价值的合成中间体，以及许多天然产物、生物活性分子和药物化合物的关键骨架。近几十年来，通过炔丙醇的直接转化合成丙二烯的合成方法的发展引起了有机化学研究人员的广泛关注。在这篇综述中，我们重点关注炔丙醇直接转化为丙二烯的最新进展。这些转化按反应类型可分为四类：（1）过渡金属催化反应；(2) 涉及碳正离子中间体的反应；(3) 金属氢化物（碱）介导的反应；(4) 涉及氧杂-炔丙基中间体的反应。