40954-63-0Relevant academic research and scientific papers
Trimethylsilyl Cyanide - A Reagent for Umpolung, XII. Intramolecular Diels-Alder Reaction of Dienals via Umpolung
Fischer, Klaus,Huenig, Siegfried
, p. 2590 - 2608 (2007/10/02)
Umpolung of dienals 1 and 2 with trimethylsilyl- or triethylsilyl cyanide and reaction with olefinic alkylating reagents 7-10 furnishes products 11-16 in high yields.On heating to 180 deg C these products, containing a diene and a dienophilic moiety, undergo in most cases quantitative intramolecular Diels-Alder reactions.Since the cycloadducts can be deprotected under very mild conditions, hexahydro-indenones (22, 25) and -naphthalinones (27, 29) can be synthesized for the first time avoiding isomerisation of the double bond.Intramolecular cycloadditions without protected carbonyl groups in the precursor (19, 21) yield hexahydronaphthalinones (30, 34) with conjugated double bonds exclusively, whereas ring closure to hexahydro-indenones (33) fails.Related examples described in the literature suffer from the same drawback.
