Highly enantioselective palladium-catalyzed formal hydrogenolysis of racemic N-sulfonyloxaziridines has been realized, providing a novel access to sultams with up to 99% ee. Preliminary mechanistic insights revealed that the reaction proceeded through a N–O bond cleavage, dehydration, and the sequential asymmetric hydrogenation.
Ni(II)/tBu-SMI-PHOX catalyzed enantioselective addition of arylboronic acids to cyclic N-sulfonyl aldimines
作者:Rui Sun、Zhongxuan Qiu、Guorui Cao、Dawei Teng
DOI:10.1016/j.tet.2020.131201
日期:2020.5
addition of arylboronic acids to cyclic N-sulfonyl aldimines is envisioned to afford excellent enantioselectivities (up to 99% ee) in high yields (up to 98%). This protocol offers new opportunities for the synthesis of chiral benzosultams containing a stereogenic tertiary carbon center. The highlights of this method include mild reaction conditions, the use of cheap metal catalyst and a wide substrate scope
设想了将有效的Ni(ClO 4)2 ·6H 2 O / SMI-PHOX催化的芳基硼酸对映选择性加成到环状N-磺酰基醛亚胺中,以高产率(高达98%)提供优异的对映选择性(高达99%ee)。 。该协议为合成含有立体异构叔碳中心的手性苯并舒坦提供了新的机会。该方法的亮点包括温和的反应条件,使用廉价的金属催化剂和广泛的底物范围。
Synthesis of chiral sultams via palladium-catalyzed intramolecular asymmetric reductive amination
A novel palladium-catalyzedintramolecular reductive amination of ketones with the low nucleophilic sulfonamides has been developed in the presence of Bronsted acid, providing a wide range of chiral [gamma]-, [small delta]-,...
Chiral sulfonylamines can be efficiently synthesized in good yields by asymmetric hydrogenation of cyclic and acyclic N‐sulfonylimines co‐catalyzed by Pd/Zn(OTf)2 using hydrogen gas under ambient pressure.
An N-heterocyclic carbene iridium catalyst with metal-centered chirality for enantioselective transfer hydrogenation of imines
作者:Yanjun Li、Meng Lei、Wei Yuan、Eric Meggers、Lei Gong
DOI:10.1039/c7cc04691j
日期:——
carbene iridium complex featuring metal-centered chirality was designed and applied to the asymmetric transfer hydrogenation (ATH) of imines. Four strongly σ-donating carbon-based substituents (2 carbenes and 2 phenyl moieties), a chirality transfer directly from the stereogenic metal center to the C=N bond of substrates, as well as a restriction of catalyst deactivation by steric demanding substituents