A divergent strategy for the facile preparation of various enantioenriched phenylthio-substituted lactones was developed based on Lewis base/Brønsted acid co-catalyzed thiolation of homoallylic acids. The acid-controlled regiodivergent cyclization (6-endo vs. 5-exo) and acid-mediated stereoselective rearrangement of phenylthio-substituted lactones were explored. Experimental and computational studies
基于路易斯碱/布朗斯台德酸共催化的均烯丙基酸的硫醇化反应,开发了一种简便制备各种对映体富集的苯硫基取代的内酯的策略。探索了酸控制的区域发散环化(6-endo vs. 5-exo)和苯硫基取代的内酯的酸介导的立体选择性重排。进行了实验和计算研究以阐明区域选择性和对映选择性的起源。计算结果表明,CO和CS键的形成可能会同时发生,而不会形成通常认为的催化剂配位的硫鎓离子中间体,而且底物和SPh之间的潜在π-π堆积是对映确定步骤的重要因素。最后,
Highly Regioselective Difluoroalkylarylation of Butadiene through a Nickel-Catalyzed Tandem Radical Process
作者:Shucheng Ma、Fangjie Li、Guisheng Zhang、Lei Shi、Xiaoming Wang
DOI:10.1021/acscatal.1c04237
日期:2021.12.17
A nickel-catalyzedreaction of 1,3-butadiene with easily accessible difluoroalkyl bromides and arylboronic acids has been realized, affording the corresponding 1,4-difluoroalkylarylation products in good yields with high regioselectivities. The procedure can also be successfully extended to nonfluorinated alkyl bromides. A radical clock experiment suggests that a key alkyl radical is involved in the
NiH-Catalyzed Proximal-Selective Hydroamination of Unactivated Alkenes
作者:Jinwon Jeon、Changseok Lee、Huiyeong Seo、Sungwoo Hong
DOI:10.1021/jacs.0c10333
日期:2020.12.2
unactivated alkenes with diverse amine sources. The key to the successful implementation of this approach is the promotion of NiH insertion into even highly substituted olefins via coordination of the bidentate directing group to the nickel complex. A wide range of primary and secondaryamines can be installed in both internal and terminal unactivated alkenes with excellent regiocontrol under the optimized
A general approach to γ-lactones via osmium-catalyzed asymmetric dihydroxylation. Synthesis of (−)- and (+)-muricatacin.
作者:Zhi-Min Wang、Xiu-Lian Zhang、K.Barry Sharpless、Subhash C. Sinha、Anjana Sinha-Bagchi、Ehud Keinan
DOI:10.1016/s0040-4039(00)79001-0
日期:1992.10
γ-lactones have been prepared highly enantioselectively (92–99% ee) using either AD-mix-β or AD-mix-α with both β,γ- and γ,δ-unsaturated esters. The method is exemplified by the three-step synthesis of (−) and (+)-muricatacin in 74% yield and >99% ee.