Synthesis of Enantiomerically Pure Allenes with Central and Axial Chirality Mediated by a Remote Sulfinyl Group
作者:José García Ruano、José Alemán、Vanesa Marcos
DOI:10.1055/s-0029-1217006
日期:2009.10
Enantiomerically pure 2-(p-tolylsulfinyl)benzylcopper reagents react with propargyl bromides and mesylates, affording enantiomerically pureallenes with central and axialchirality. Both regioselectivity (SN2′ processes) and configuration at the chiral axis are completely controlled by the sulfinylgroup. The stereoselectivity at the benzylic position is very high. Complete kinetic resolution and moderate
对映体纯的2-(对甲苯基亚磺酰基)苄基铜试剂与炔丙基溴和甲磺酸酯反应,得到具有中心和轴向手性的对映体纯的烯。区域选择性(S N 2'过程)和在手性轴上的构型均完全由亚硫酰基控制。在苄基位置的立体选择性非常高。可以实现外消旋炔丙基甲磺酸酯的完全动力学拆分和中等动态拆分。可以通过假设亚砜基氧使苄基铜稳定并作为分子内S N 2'亲核进攻的前一步,将三键与金属缔合来解释这种立体化学行为。 丙二烯-亚磺酰基-轴向手性-中心手性-不对称合成
Synthesis of amino allenes via reaction of α-aminoalkylcuprates with propargyl substrates
作者:R.Karl Dieter、Lois E Nice
DOI:10.1016/s0040-4039(99)00778-9
日期:1999.6
α-Aminoalkylcuprates prepared from carbamates via sequential deprotonation and treatment with CuCN·2LiCl react with propargyl bromides, mesylates, tosylates, acetates, and epoxides to afford amino allenesvia a SN2′ substitution process. Propargyl bromides and sulfonates give good yields of amino allenes while the acetates afford low yields. Substrates undergo regiospecific SN2′ substitution and the
由氨基甲酸酯经顺序去质子化制得的α-氨基烷基铜酸酯,并用CuCN·2LiCl处理,与炔丙基溴,甲磺酸酯,甲苯磺酸酯,乙酸酯和环氧化物反应,经S N 2'取代过程制得氨基丙二烯。炔丙基溴和磺酸盐提供了良好的氨基丙二烯收率,而乙酸酯提供了低收率。底物进行区域特异性S N 2'取代,使用Sc(OTf)3可提高炔丙基环氧化物的氨基丙二烯收率。Boc保护的α-氨基丙二烯可以环化为恶唑烷酮或脱保护得到游离胺。
PdCl<sub>2</sub>-Catalyzed Efficient Transformation of Propargylic Amines to (<i>E</i>)-α-Chloroalkylidene-β-lactams
作者:Shengming Ma、Bin Wu、Xuefeng Jiang
DOI:10.1021/jo0480996
日期:2005.4.1
The PdCl2-catalyzed cyclocarbonylation reaction of propargylic amines with CuCl2 and benzoquinone afforded (E)-alpha-chloroalkylidene-beta-lactams in moderate to good yields. The formation of the corresponding Z-isomers or five-membered products was not observed. The reaction of the readily available optically active propargylic amines provides a convenient synthesis of the corresponding (E)-alpha-chloroalkylidene-beta-lactams with high ee values. The structure and the stereochemistry of the products were established by the X-ray single-crystal diffraction study of (E)-6d and (E)-6e, which indicates that the stereoselectivity in this reaction is different from what was observed with propargylic alcohols. A rationale for this reaction was proposed.
Configurational Control of Benzyl Carbanion-Copper Complexes by Sulfinyl Groups: Synthesis of Optically Pure Allenes with Central and Axial Chirality
作者:José Luis García Ruano、Vanesa Marcos、José Alemán