Enantioselective Conjunctive Cross-Coupling of Bis(alkenyl)borates: A General Synthesis of Chiral Allylboron Reagents
作者:Emma K. Edelstein、Sheila Namirembe、James P. Morken
DOI:10.1021/jacs.7b01774
日期:2017.4.12
conjunctive cross-coupling is used for the synthesis of enantioenriched allylboron reagents. This reaction employs nonsymmetric bis(alkenyl)borates as substrates and appears to occur by a mechanism that involves selective activation of the less substituted alkene followed by migration of the more substituted alkene during the course of a Pd-induced metalate rearrangement.
Bis(oxazolinyl)phenylrhodium(III) Aqua Complex: Efficiency in Enantioselective Addition of Methallyltributyltin to Aldehydes under Aerobic Conditions
作者:Yukihiro Motoyama、Hisao Nishiyama
DOI:10.1055/s-2003-41474
日期:——
A simple and general protocol is described for the enantioselective addition of methallyltributyltin to aldehydes catalyzed by chiral (Phebox)RhCl2(H2O) complexes 1 [Phebox = 2,6-bis(oxazolinyl)phenyl]. The reaction can be performed even under aerobic conditions to afford the corresponding optically active homoallylic alcohols in good yields with high enantioselectivities (90-99% ee).
Asymmetric Catalysis of Nozaki−Hiyama Allylation and Methallylation with A New Tridentate Bis(oxazolinyl)carbazole Ligand
作者:Masahiro Inoue、Takahiro Suzuki、Masahisa Nakada
DOI:10.1021/ja021243p
日期:2003.2.1
the asymmetric catalysis of Nozaki-Hiyama allylation and methallylation. Various aldehydes were allylated or methallylated with good enantioselectivity (86-96%), and a key intermediate of calcitriol lactone synthesis was also obtained with excellent diastereoselectivity (97% de, 91%). The enantioselective reaction catalyzed by this Cr-ligand complex is applicable to a broad range of aldehydes and has
这项工作描述了对 Nozaki-Hiyama 烯丙基化和甲基烯丙基化的不对称催化有效的新三齿配体的开发。各种醛以良好的对映选择性(86-96%)烯丙基化或甲基烯丙基化,并以优异的非对映选择性(97% de, 91%)获得骨化三醇内酯合成的关键中间体。由这种 Cr-配体配合物催化的对映选择性反应适用于广泛的醛类,在天然产物合成方面具有巨大潜力。这种配体的另一个显着特征是 Cr-配体复合物的稳定性,它在对映选择性反应后回收并循环两次,而不会降低对映选择性和产率。
Enantioselective Addition of Methallyl- and Crotyltins to Aldehydes Catalyzed by BINAP×Ag(I) Complex
Reaction of aldehydes with methallyltributyltin or crotyltributyltin in the presence of a catalytic amount of BINAP×silver(I) complex affords the corresponding optically active homoallylic alcohols with high enantioselectivities; γ- and antiselectivities are also obtained for crotyltributyltin.
A highly enantioselective allylation reaction of aldehydes with silyl reagents was developed for the synthesis of a variety of chiral homoallylic alcohols. In the presence of a chiral oxazaborolidinium ion (COBI) catalyst, the reaction proceeded in high yield (up to 99%) with excellent asymmetric induction (up to 99% ee).