Catalyst-Controlled Diastereodivergent Synthesis of Dispiro Compounds via Formal (3 + 2) Cyclization
Li Xiang1,2, Ying-Mei Li1,2, You-Ping Tian1,2
1School of Pharmacy, Guizhou University of Traditional Chinese Medicine, Guiyang, 550025, P. R. China.
None:
Mg/Pd-catalyzed the same formal (3 + 2) cycloaddition of spirovinylcyclopropyl oxindoles and 2-arylidene-1,3-indanediones was realized for the first time. The protocol enables access to two diastereomers of dispiro pentacyclic compounds in good to excellent yields (up to 94%) with acceptable dr (up to >20:1:0:0 dr). Based on experimental results and a high-resolution mass spectrometry experiment, a plausible reaction mechanism and a tentative model of Mg-/Pd-controlled diastereosegregation have been proposed, revealing the reason for the highly diastereoselective generation of the major product.
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