Tanpure Subhash D, El-Mansy Mohamed F, Blakemore Paul R
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003, United States.
Org Lett. 2020 Apr 17;22(8):2999-3003. doi: 10.1021/acs.orglett.0c00755. Epub 2020 Mar 31.
To gauge the feasibility of carbenoid eliminative cross-coupling for the synthesis of polyfunctional alkenes, a P-glycoprotein inhibitor containing an ()-configured 4-chromanylidene-type trisubstituted olefin was prepared as well as its previously undescribed ()-isomer. Stereospecific alkene synthesis required generation of functionalized enantioenriched α-metalated carbamates [RRCM(OCN-Pr), 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.
为评估类卡宾消除交叉偶联用于合成多官能烯烃的可行性，制备了一种含有（）构型的4-色满亚基型三取代烯烃的P-糖蛋白抑制剂及其之前未描述的（）异构体。立体有择烯烃合成需要生成官能化的对映体富集α-金属化氨基甲酸酯[RRCM(OCN-Pr)，M = Li或Bneo]，并遇到了与锂化区域选择性不正确以及意外的有机锂构型不稳定性相关的问题。阐述了这些困难的解决方案以及一种测定α-氨基甲酰氧基硼酸酯对映体过量的方法。
