Efficient asymmetric syntheses of naturally occurring lignan lactones using catalytic asymmetric hydrogenation as a key reaction
作者:Toshiaki Morimoto、Mitsuo Chiba、Kazuo Achiwa
DOI:10.1016/s0040-4020(01)80536-6
日期:1993.2
using the catalytic asymmetric hydrogenation of arylidenesuccinic acid monoesters with a rhodium(I) complex of a chiral bisphosphine, (4S,5S)-MOD-DIOP. Asymmetric total syntheses of some naturallyoccurringlignans, (+)-collinusin, (−)-deoxypodophyllotoxin, and (+)-neoisostegane, were achieved via several steps from (R)-γ-butyrolactones as key intermediates obtained by the reduction of (R)-arylmethylsuccinic
Ruthenium catalyst for biarylic coupling; new steganolides
申请人:Universite Du Maine (Le Mans)
公开号:US04873349A1
公开(公告)日:1989-10-10
A method for forming bridged biaryl compounds via the intramolecular oxidative biarylic coupling of precursor compounds containing two aromatic rings linked via a hydrocarbon chain is disclosed along with the ruthenium catalyst for its implementation and new compounds resulting therefrom. The biarylic coupling method is characterized in that the biarylic precursors are cyclized in the presence of the catalyst tetrakis(trifluoroacetate) of ruthenium (IV).
The asymmetric allylation under the assistance of catalytic amounts of 3,3′-bis(2,4,6-triisopropylphenyl)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate (TRIP) allows the concise construction of the lignan scaffold from simple aldehydes and allylic bromides with full control of the two formed stereocenters. This young methodology has been employed to synthesize four naturally and pharmaceutically active