Concurrent Induction of Two Chiral Centers from Symmetrical 3,4-Disubstituted and 3,3,4-Trisubstituted 4-Pentenals Using Rh-Catalyzed Asymmetric Cyclizations

Autor:	Masakazu Tanaka, Xiao-Ming Wu, Kazuhisa Funakoshi, Masanori Imai, Kiyoshi Sakai, Masakazu Fujio, Yasuko Eto-Kato, Miyuki Takahashi, Eishi Sakamoto, Hiroshi Suemune
Rok vydání:	2000
Předmět:	chemistry.chemical_classification Deuterium Catalytic cycle Chemistry Ligand Organic Chemistry Cationic polymerization Optically active Medicinal chemistry Aldehyde Quaternary carbon Catalysis
Zdroj:	The Journal of Organic Chemistry. 65:5806-5816
ISSN:	1520-6904 0022-3263
DOI:	10.1021/jo000781m
Popis:	Asymmetric cyclization of symmetrical 3,4-disubstituted and 3,3, 4-trisubstituted 4-pentenals was studied using Rh-complexes with chiral ligands. The cyclization of symmetrical 4-pentenals 4a,b by a neutral Rh[(R)-BINAP]Cl afforded cis-3,4-disubstituted (4R)-cyclopentanones 9a,b of95% ee in 25-31% yields; on the other hand, the cyclization of 4a-c by a cationic Rh[(R)-BINAP]ClO(4) afforded trans-3,4-disubstituted (4S)-cyclopentanones 10a-c of95% ee in 70-81% yields. All stereoisomers could be stereoselectively made by the selection of a neutral or cationic Rh-complex, and (R)- or (S)-BINAP ligand. The Rh-catalyzed cyclization could be applied to the construction of cyclopentanones 17 and 18 bearing a chiral quaternary carbon. The cyclization by the cationic Rh[(R)-BINAP]ClO(4) afforded the optically active trans-3,3, 4-trisubstituted cyclopentanones 18a-c of 92-95% ee in 75-83% yields. The catalytic cycle was also studied by using deuterium aldehyde, and the tentative mechanisms of the enantio- and diastereoselection were proposed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::59751fd091e45cc9038227f0b7488fb9 https://doi.org/10.1021/jo000781m Zobrazit plný text záznamu