由手性仲烷基碘化物通过保留性I / Li交换,然后用CuBr⋅P(OEt)3进行保留性重金属化,制备了手性仲烷基铜试剂。将溶剂转换为THF可显着提高其构型稳定性,并使这些铜试剂适合于区域选择性的烯丙基取代。光学富集的铜物质经过烯丙基溴的S N 2取代(最高> 99%S N 2区域选择性)。ZnCl 2的添加和手性烯丙基磷酸酯的使用允许将区域选择性转向S N 2'取代(高达> 99%S N 2'区域选择性)并执行高度选择性的抗-S N 2'替换,具有对两个相邻立体中心的绝对控制。该方法用于三种蚂蚁信息素(+)-紫杉醇,(+)-13-正法烷醛和(+)-法烷醛的合成(最高98:2 dr,99%ee)。
Mild and Phosphine-Free Iron-Catalyzed Cross-Coupling of Nonactivated Secondary Alkyl Halides with Alkynyl Grignard Reagents
作者:Chi Wai Cheung、Peng Ren、Xile Hu
DOI:10.1021/ol501087m
日期:2014.5.2
cross-coupling of nonactivated secondary alkylbromides and iodides with alkynyl Grignardreagents at room temperature has been developed. A wide range of secondary alkyl halides and terminal alkynes are tolerated to afford the substituted alkynes in good yields. A slight modification of the reaction protocol also allows for cross-coupling with a variety of primary alkyl halides.
Stereospecific Electrophilic Fluorination of Alkylcarbastannatrane Reagents
作者:Xinghua Ma、Mohamed Diane、Glenn Ralph、Christine Chen、Mark R. Biscoe
DOI:10.1002/anie.201704672
日期:2017.10.2
Speed matters: Site-specific fluorination reactions of isolable primary and secondary alkylcarbastannatrane nucleophiles occur fast, without the need for transition metal catalysis, or in situ activation of the nucleophile. The reaction conditions can also be extended to stereospecific chlorination, bromination, and iodination reactions.
converted into secondary alkyllithium and secondary alkylcopper compounds with very high retention of configuration. Quenching with various electrophiles, including chiral epoxides, provided a range of chiral molecules with high enantiomericpurity (>90 % ee). This method has been applied in an iterative fashion in the total synthesis of (−)‐lardolure in 13 steps and 5.4 % overall yield (>99 % ee, dr>99:1)
NiH-Catalyzed Reductive Relay Hydroalkylation: A Strategy for the Remote C(sp<sup>3</sup>
)−H Alkylation of Alkenes
作者:Fang Zhou、Jin Zhu、Yao Zhang、Shaolin Zhu
DOI:10.1002/anie.201712731
日期:2018.4.3
The terminal‐selective, remoteC(sp3)−H alkylation of alkenes was achieved by a relay process combining NiH‐catalyzed hydrometalation, chain walking, and alkylation. This method enables the construction of unfunctionalized C(sp3)−C(sp3) bonds under mild conditions from two simple feedstock chemicals, namely olefins and alkyl halides. The practical value of this transformation is further demonstrated
Two‐Step Protocol for Iodotrimethylsilane‐Mediated Deoxy‐Functionalization of Alcohols
作者:Yuming Chen、Ru He、Hongjian Song、Guoqing Yu、Chenglin Li、Yuxiu Liu、Qingmin Wang
DOI:10.1002/ejoc.202001602
日期:2021.2.19
protocol for iodotrimethylsilane‐mediated deoxy‐functionalization of primary and secondaryalcohols was described. This protocol involves iodination of alcohol and then replaced by a N, S, or O nucleophile. Compared with traditional Mitsunobureaction, non‐acidic pre‐nucleophiles can be used in this protocol and configuration of alcohols can be retained.