Synthesis of α-Quaternary Formimides and Aldehydes through Umpolung Asymmetric Copper Catalysis with Isocyanides
作者:Kentaro Hojoh、Hirohisa Ohmiya、Masaya Sawamura
DOI:10.1021/jacs.6b12881
日期:2017.2.15
A highly regio- and enantioselective copper-catalyzed three-component coupling of isocyanides, hydrosilanes, and γ,γ-disubstituted allylic phosphates/chlorides to afford chiral α-quaternary formimides was enabled by the combined use of our original chiral naphthol-carbene ligand as a functional Cu-supporting ligand and LiOtBu as a stoichiometric Lewis base for Si. The formimides were readily converted
通过结合使用我们原始的手性萘酚-卡宾配体,实现了高度区域选择性和对映选择性铜催化的异氰化物、氢硅烷和 γ,γ-二取代的烯丙基磷酸酯/氯化物的三组分偶联,以提供手性 α-季铵甲酰亚胺。功能性 Cu 支持配体和 LiOtBu 作为 Si 的化学计量路易斯碱。甲酰亚胺很容易转化为α-季醛。
Enantioselective Synthesis of All-Carbon Quaternary Stereogenic Centers via Copper-Catalyzed Asymmetric Allylic Alkylation of (<i>Z</i>)-Allyl Bromides with Organolithium Reagents
作者:Martín Fañanás-Mastral、Romina Vitale、Manuel Pérez、Ben L. Feringa
DOI:10.1002/chem.201406006
日期:2015.3.9
A copper/phosphoramidite catalyzed asymmetric allylic alkylation of Z trisubstituted allyl bromides with organolithium reagents is reported. The reaction affords all‐carbon quaternary stereogenic centers in high yields and very good regio‐ and enantioselectivity. This systematic study illustrates the crucial role of the olefin geometry of the allyl substrate on the outcome of the reaction and provides
Cyclopentanones 3 and 7 are generated in a one-pot procedure from allyl vinyl ethers 1 and diallyl ethers 4, respectively. The conversion is carried out in the presence of RhCl(cod)(dppe) or RuCl2(PPh3)3 at elevated temperatures and involves a sequence of aliphatic Claisen rearrangement and intramolecular hydroacylation of the pent-4-enals generated as intermediates. The diallyl ethers 4 undergo an additional double-bond isomerization prior to the Claisen rearrangement.
Highly stereoselective and general synthesis of (z)-3-methyl-2-alken-1-ols via palladium-catalyzed cross coupling of (z)-3-iodo-2-buten-1-ol with organozincs and other organometals
作者:Ei-ichi Negishi、Mehmet Ay、Yuri V. Gulevich、Yumiki Noda
DOI:10.1016/s0040-4039(00)60312-x
日期:1993.2
The reaction of Zn-protected (Z)-3-iodo-2-buten-1-ol with organozincs in the presence of 1-5 mol % of a Pd complex, e.g., Pd(PPh3)4 or Cl2Pd(pPh3)2 and n-BuLi (2 equiv), in DMF provides a highly stereoselective (greater-than-or-equal-to 96%), general, and high-yielding procedure for preparing (Z)-3-methyl-2-alken-1-ols, while the use of organometals containing B and Sn along with a Pd catalyst or organocoppers alone gives the desired products in moderate to good yields.