Enantioselective Trapping of Pd-Containing 1,5-Dipoles by ......In conclusion, we have successfully...
Transcript of Enantioselective Trapping of Pd-Containing 1,5-Dipoles by ......In conclusion, we have successfully...
In conclusion, we have successfully achieved the first visible light-
induced, Pd-catalyzed asymmetric [5+2] cycloaddition of VECs with α-
diazoketones. This methodology provides an enantioselective approach for
accessing a variety of 7-membered lactones bearing chiral quaternary
stereocenters. Preliminary mechanistic studies suggested that the binding of
two phosphoramidite ligands to the palladium center was responsible for
the high reaction efficiency and enantioselectivity. The transformation
described in this work represents a significant expansion of ketene
chemistry into the construction of challenging medium-sized rings.
Enantioselective Trapping of Pd-Containing 1,5-Dipoles by Photo-generated Ketenes: Access to 7-Membered Lactones Bearing Chiral Quaternary Stereocenters
Yi Wei, Song Liu, Miao-Miao Li, Yi Li, Yu Lan, Liang-Qiu Lu,* and Wen-Jing Xiao*
Wei, Y.; Liu, S.; Li, M.-M.; Li, Y.; Lan, Y.; Lu, L.-Q.;* Xiao, W.-J. * J. Am. Chem.
Soc., 2019, 141, 133–137.
AcknowledgmentWe are grateful to the National Science Foundation of China (No. 21822103, 21820102003, and 21472057), the Program of
Introducing Talents of Discipline to Universities of China (111 Program, B17019) for support of this research.
College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan, Hubei, China, 430079
Conclusion 7
References 8
Proposed Stereoinduction Modes6
Introduction 1
Reaxys PhD Prize Symposium 2019, October 3-4, Amsterdam, Netherlands.
Reaction Design2
Construction of medium-sized rings in an efficient
and selective way is an important and challenging task in
organic synthesis. Among the ongoing efforts towards this
goal, [5+2] cycloadditions using reactive transition metal
(TM)-containing 1,5-dipolar synthons is a promising approach to
7-membered rings possibly due to the ready availability of the precursors.
However, the successful asymmetric variants have been largely limited to
intramolecular Ru- or Rh-catalyzed processes using chiral feedstocks. To
make TM-catalyzed dipolar cycloadditions more powerful and general in
the synthesis of medium-sized rings, new strategies for achieving these
transformation in high efficiency and selectivity and under mild reaction
conditions are required.
Nonlinear Experiments.4
ESI-MS Analysis of the Pd Complexes5
Selected Results3