Synthesis 2022; 54(10): 2433-2446
DOI: 10.1055/s-0040-1719883
paper

Rh2(esp)2-Catalyzed Redox/Cycloaddition Cascade of Diazoaceto­acetate Enones with N-Methyl Nitrones: Diastereoselective Synthesis of β-Lactams with Two Adjacent Chiral Centers

Yingjun Zhao
,
Rujie Xu
,
Zhengqing Xu
,
Xichen Xu

This work was supported by the National Natural Science Foundation of China (21801198), the Wuhan Institute of Technology (17QD05), and the Graduate Innovative Fund of the Wuhan Institute of Technology (CX2020280).


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Abstract

A Rh2(esp)2-catalyzed diastereoselective synthesis of highly functionalized β-lactams is developed. By employing Rh2(esp)2 as the catalyst, a reaction cascade operates by reducing an N-methyl nitrone to the corresponding N-methyl imine in the presence of a first molecule of the diazoacetoacetate enone. A second molecule of the diazoacetoacetate enone sensing a change in the reaction medium undergoes a Wolff rearrangement to afford a vinyl ketene. This vinyl ketene then reacts with the in situ generated N-methyl imine to diastereoselectively furnish a β-lactam with two contiguous stereogenic centers. Extension of this method to the [2+2]-cycloaddition of PMB-protected imines and diazoacetoacetate enones catalyzed by Rh2(esp)2 is also reported.

Supporting Information



Publication History

Received: 22 November 2021

Accepted after revision: 16 December 2021

Article published online:
01 February 2022

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