The Fischer carbene synthesis, involving the conversion of a transition metal (TM)-bound CO ligand to a carbene ligand of the form [=C(OR’)R] (R, R’ = organyl groups), is one of the seminal reactions in the history of organometallic chemistry. Carbonyl complexes of p-block elements, of the form [E(CO)_n] (E = main-group fragment), are much less abundant than their TM cousins; this scarcity and the general instability of low-valent p-block species means that replicating the historical reactions of TM carbonyls is often very difficult. Here we present a step-for-step replica of the Fischer carbene synthesis at a borylene carbonyl involving nucleophilic attack at the carbonyl carbon followed by electrophilic quenching at the resultant acylate oxygen atom. These reactions provide borylene acylates and alkoxy-/silyloxy-substituted alkylideneboranes, main-group analogues of the archetypal transition metal acylate and Fischer carbene families, respectively. When either the incoming electrophile or the boron center has a modest steric profile, the electrophile instead attacks at the boron atom, leading to carbene-stabilized acylboranes – boron analogues of the well-known transition metal acyl complexes. These results constitute faithful main-group replicas of a number of historical organometallic processes and pave the way to further advances in the field of main-group metallomimetics.

Fischer 卡宾合成，涉及将过渡金属 (TM) 结合的 CO 配体转化为 [=C(OR')R]（R，R' = 有机基团）形式的卡宾配体，是开创性的方法之一有机金属化学史上的反应。p-嵌段元素的羰基络合物，形式为 [E(CO) _n]（E = 主族片段），比它们的 TM 表亲少得多；这种稀缺性和低价 p-block 物种的普遍不稳定性意味着复制 TM 羰基的历史反应通常非常困难。在这里，我们展示了在亚硼烷羰基处 Fischer 卡宾合成的逐步复制品，涉及对羰基碳的亲核攻击，然后在所得的酰化氧原子上进行亲电猝灭。这些反应提供亚硼烯酰化物和烷氧基-/甲硅烷氧基-取代的亚烷基硼烷，分别是原型过渡金属酰化物和 Fischer 卡宾家族的主族类似物。当进入的亲电子试剂或硼中心具有适度的空间分布时，亲电子试剂反而攻击硼原子，导致卡宾稳定的酰基硼烷——众所周知的过渡金属酰基络合物的硼类似物。这些结果构成了许多历史有机金属过程的忠实主族复制品，并为主族金属模拟学领域的进一步发展铺平了道路。