To gauge the feasibility of carbenoid eliminative cross-coupling for the synthesis of polyfunctional alkenes, a P-glycoprotein inhibitor containing an (E)-configured 4-chromanylidene-type trisubstituted olefin was prepared as well as its previously undescribed (Z)-isomer. Stereospecific alkene synthesis required generation of functionalized enantioenriched α-metalated carbamates [R¹R²CM(O₂CNi-Pr₂), M = Li or Bneo], and problems associated with incorrect lithiation regioselectivity and unexpected organolithium configurational lability were encountered. Solutions to these difficulties are described together with a method for ee determination of α-carbamoyloxyboronates.

中文翻译：

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类胡萝卜素消除交叉偶联合成P-糖蛋白抑制剂及其高能（Z）-异构体。

为了评估类胡萝卜素消除交叉偶联用于合成多官能烯烃的可行性，制备了包含（E）-构型的4-苯并二氢萘基型三取代烯烃的P-糖蛋白抑制剂及其先前未描述的（Z）-异构体。立体定向烯烃的合成需要生成功能化的对映体富集的α-金属氨基甲酸酯[R ¹ R ² CM（O ₂ CN i -Pr ₂），M = Li或Bneo]，并且遇到了与不正确的锂化区域选择性和意外的有机锂构型不稳定性相关的问题。描述了解决这些难题的方法，以及用于ee测定α-氨基甲酰氧基硼酸酯的方法。