Intramolecular 1,3-dipolar cycloadditions of dihydroimidazolium ylides: synthesis of pyrrolo[1,2,3-de]quinoxalines and imidazo[1,2-a]indoles
作者:Pedro M. J. Lory、Raymond C. F. Jones、James N. Iley、Simon J. Coles、Michael B. Hursthouse
DOI:10.1039/b605458g
日期:——
an intramolecular 1,3-dipolar cycloaddition reaction that affords (via a reaction cascade involving eliminative ring-opening, recyclisation and prototropic tautomerism) unexpected hexahydropyrrolo[1,2,3-de]quinoxaline products. Steric bulk in both the dihydroimidazole and the dipolarophile allows isolation of an imidazo[1,2-a]indole, the initial product of cycloaddition. When the bromomethyl ketone
Further observations on the rhodium (I)-catalysed tandem hydrosilylation-intramolecular aldol reaction
作者:Marta Freirı́a、Andrew J Whitehead、Derek A Tocher、William B Motherwell
DOI:10.1016/j.tet.2003.12.057
日期:2004.3
The rhodium (I) catalysed tandem hydrosilylation-intramolecular aldol reaction provides a simple strategy for construction of a range of usefully functionalised five-membered rings from readily prepared 6-oxo-2-hexenoates in good yield and with good to excellent stereoselectivity. A series of silanes and rhodium catalysts have been investigated. Stereoselectivity proved to be highly dependant on the
Benzylic amines 8 react with ketoenoates 7 yielding, after reduction of the primary adducts, 2,5-dialkylpyrrolidines 9 (trans isomer predominating). This reaction has been applied to the synthesis of trans 2-heptyl-5-ethylpyrrolidine, a component of the venom of fire ant (Solenopsis punctaticeps).
Facile construction of 6-carbomethoxymethyl-3-methoxy-1,2-dioxane, a core structure of spongean anti-malarial peroxides
Facile construction of 6-carbomethoxymethyl-3-methoxy-1,2-dioxane. the Core Structure of spongean anti-malarial peroxides. has been developed by combination of Sc(OTf)(3)-mediated peroxyhemiacetalization of keto-ester and Michael addition of the resultant peroxyhemiacetal in the fluorinated alcohol. (C) 2001 Elsevier Science Ltd. All rights reserved.