ISSN:
0009-2940
Schlagwort(e):
Cyclopentanes, trans-1,2-disubstituted
;
Allylsilanes
;
Knoevenagel condensation
;
Ene reaction
;
Chemistry
;
Inorganic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The alkylidene 1,3-dioxo compounds 4a-d with an allylsilane moiety undergo a fluoride-, Lewis acid- and TMSOTf-induced intramolecular cyclisation to give almost exclusively the trans-1,2-disubstituted cyclopentanes 5a-d in good to excellent yields. The diastereoselectivity of the reaction was determined as a function of the 1,3-dioxo moiety and the inductor. The best results were obtained with FeCl3/Al2O3 followed by TMSOTf and Me2AlCl1 the highest selectivity was found in the cyclisation of 4b with TMSOTf leading to 5b and 6b in a ratio of 99.8:0.2. FeCl3/Al2O3 and TMSOTf have not previously been used for this type of reaction. The alkylidene 1,3-dioxo compounds 4a-d were synthesised by Knoevenagel condensation of the aldehyde 11 with the malonic acid derivatives 11a-d.
Zusätzliches Material:
1 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/cber.19901230631
