Biotransformations of bicyclic trimethylcyclohexane chloro-, bromo- and iodolactones using fungal strains
摘要:
Several fungal strains (Fusarium, Botrytis, Beauveria) were screened for their ability to transform three bicyclic halo-gamma-lactones with a trimethylcyclohexane ring. Most of the micro-organisms carried out hydrolytic dehalogenation and transformed these lactones into two hydroxy-gamma-lactones: cis (-)-2-hydroxy-4,4,6-trimethyl-9-oxabicyclo[4.3.0]nonan-8-one and trans (+)-2-hydroxy- 4,4,6-trimethyl-9-oxabicyclo[4.3.0]nonan-8-one. The structures of all substrates and products were established on the basis of their spectral data and X-ray analysis. The method presented offers an alternative route to obtaining hydroxy-lactones with high enantiomeric excess.
[reaction: see text] The readily available N-(O-ethyl thiocarbonylsulfanyl)amides are powerful amidyl radical precursors that undergo 5-exo cyclization to give pyrrolidinone derivatives via a radical-chain reaction initiated by a small amount of lauroyl peroxide.
Inversion of the Direction of Stereoinduction in the Coupling of Chiral γ,δ-Unsaturated Fischer Carbene Complexes with <i>o</i>-Ethynylbenzaldehyde
作者:Binay K. Ghorai、Suneetha Menon、Dennis Lee Johnson、James W. Herndon
DOI:10.1021/ol025808y
日期:2002.6.1
[GRAPHICS]A variety of gamma,delta-unsaturated carbene complexes that feature a stereogenic center at the beta-carbon couple with 2-ethynylbenzaldehyde to afford hydrophenanthrene derivatives with a high degree of stereoinduction. The direction of stereoinduction is opposite for examples where the stereogenic center is acyclic vs examples where it is within a ring.
Lactones 30. Reaction of halolactones with trialkylphosphites
作者:Bartłomiej Pisarski、Czesław Wawrzeńczyk
DOI:10.1016/j.tetlet.2006.07.052
日期:2006.9
The reaction of halolactones with trialkylphosphites in the presence of water afforded dehalogenated lactones. (c) 2006 Elsevier Ltd. All rights reserved.
Acceleration of the orthoester Claisen rearrangement by clay catalyzed microwave thermolysis: expeditious route to bicyclic lactones
作者:Robert S. Huber、Graham B. Jones
DOI:10.1021/jo00047a041
日期:1992.10
Grabarczyk; Szumny; Gladkowski, Polish Journal of Chemistry, 2005, vol. 79, # 11, p. 1763 - 1771