Organisch-Chemisches Institut , Westfälische Wilhelms-Universität Münster , Corrensstraβe 40 , 48149 Münster , Germany.
J Am Chem Soc. 2018 Mar 14;140(10):3551-3554. doi: 10.1021/jacs.8b00868. Epub 2018 Feb 28.
The highly enantioselective [5 + 2] annulation of enals with vinylethylene carbonates through a cooperative N-heterocyclic carbene (NHC)/Pd catalytic system is reported. The use of a bidentate phosphine ligand was crucial to prevent coordination of the NHC organocatalyst to the active Pd catalyst. The complementary and matched combination of the chiral NHC catalyst and chiral phosphine ligand promotes high levels of both reactivity and enantioselectivity (mostly ≥99% ee).
本文报道了通过协同 N-杂环卡宾（NHC）/Pd 催化体系，高对映选择性地实现烯醛与乙烯基碳酸乙烯酯的 [5 + 2] 环加成反应。使用双齿膦配体对于防止 NHC 有机催化剂与活性 Pd 催化剂的配位至关重要。手性 NHC 催化剂和手性膦配体的互补和匹配组合促进了高反应活性和对映选择性（大多数情况下≥99%ee）。
