Catalytic cross-metathesis (CM) reactions that can generate trisubstituted alkenes in high stereoisomeric purity are important but remain limited in scope. Here, CM reactions are introduced that generate Z-trisubstituted α-methyl, α,β-unsaturated, alkyl and aryl esters, thiol esters, and acid fluorides. Transformations are promoted by a Mo bis-aryloxide, a monoaryloxide pyrrolide, or a monoaryloxide chloride complex; air-stable and commercially available paraffin tablets containing a Mo complex may also be used. Alkyl, aryl, and silyl carboxylic esters as well as thiol esters and acid fluoride reagents are either purchasable or can be prepared in one step. Products were obtained in 55–95% yield and in 88:12–>98:2 Z/E ratio (typically >95:5). The applicability of the approach is highlighted by a two-step conversion of citronellol to an isomintlactone precursor (1.7 g, 73% yield, and 97:3 Z/E) and a single-step transformation of lanosterol acetate to 3-epi-anwuweizic acid (72% yield and 94:6 Z/E). Included are the outcomes of DFT studies, regarding several initially puzzling catalyst activity trends, providing the following information: (1) it is key that a disubstituted Mo alkylidene, generated by a competing homo-metathesis (HM) pathway, can re-enter the productive CM cycle. (2) Whereas in a CM cycle the formation of a molybdacyclobutane is likely turnover-limiting, the collapse of related metallacycles in a HM cycle is probably rate-determining. It is therefore the relative energy barrier required for these steps that determines whether CM or HM is dominant with a particular complex.

中文翻译：

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Z-三取代 α,β-不饱和酯和酸性氟化物通过立体控制催化交叉复分解

可以生成高立体异构纯度的三取代烯烃的催化交叉复分解 (CM) 反应很重要，但范围仍然有限。在这里，引入了 CM 反应，生成Z-三取代的 α-甲基、α,β-不饱和、烷基和芳基酯、硫羟酸酯和酰基氟。Mo bis-aryloxide、monoaryloxide pyrrolide 或 monoaryloxide chloride 络合物可促进转化；也可以使用含有 Mo 络合物的空气稳定的市售石蜡片。烷基、芳基和甲硅烷基羧酸酯以及硫羟酸酯和酰基氟试剂均可购买或一步制备。以 55–95% 的收率和 88:12–>98:2 Z / E获得产品比率（通常 >95:5）。该方法的适用性通过将香茅醇两步转化为异薄荷内酯前体（1.7 g，73% 产率和 97:3 Z / E）以及将羊毛甾醇乙酸酯一步转化为 3- epi -anwuweizic来突出显示酸（72% 产率和 94:6 Z / E). 包括 DFT 研究的结果，关于几个最初令人费解的催化剂活性趋势，提供以下信息：(1) 由竞争性同位复分解 (HM) 途径产生的二取代的 Mo 亚烷基可以重新进入催化剂的关键富有成效的 CM 周期。(2) 而在 CM 循环中，钼环丁烷的形成可能限制周转，而 HM 循环中相关金属环的崩溃可能决定速率。因此，这些步骤所需的相对能量势垒决定了 CM 或 HM 是否对特定复合物占主导地位。