Stereoselective synthesis of new (+)-1-{(1R,3R,6S)-4,7,7-trimethylbicyclo[4.1.0]hept-4-en-3-yl}ethan-1-one derivatives
摘要:
A procedure was developed for the stereoselective synthesis of aminated derivatives of (+)-1-{(1R,3R,6S)-4,7,7-trimethylbicyclo[4.1.0]hept-4-en-3-yl}ethan-1-one. The configuration of the sidechain chiral center in (+)-1-{(1R,3R,6S)-4,7,7-trimethylbicyclo[4.1.0]hept-4-en-3-yl}ethan-1-ol was determined by X-ray analysis. Diketene and Meldrum's acid were proposed as initial compounds for the synthesis of, respectively, 3-oxobutanoic and malonic acid esters having a 1-ethyl-4,7,7-trimethylbicyclo[4.1.0]hept-4-ene fragment.
Bromenium-Catalysed Tandem Ring Opening/Cyclisation of Vinylcyclopropanes and Vinylcyclobutanes: A Metal-Free [3+2+1]/[4+2+1] Cascade for the Synthesis of Chiral Amidines and Computational Investigation
reaction has been further extended to vinylcyclobutane systems and involves a [4+2+1] cascade cyclisation with the same reagents. The versatility of the methodology has been demonstrated by careful choice of VCPs and VCBs to yield bicyclo[4.3.0]‐, ‐[4.3.1]‐ and ‐[4.4.0]amidines in enantiomerically pure form. On the basis of the experimental observations and DFT calculations, a reasonable mechanism has
Photoinduced vinylcyclopropane-cyclopentene rearrangement: A methodology for chiral bicyclo[3.2.0]heptenes. Formai syntheses of (±)-grandisol and naturally occurring ()-Δ9(12)-Capnellene and its antipode
作者:Harikisan R. Sonawane、Vishwaniyant G. Naik、Nanjundiah S. Bellur、Virendra G. Shah、Pramod.C. Purohit、M.Uday Kumar、Dilip G. Kulltarni、Jaimala R. Ahuja
DOI:10.1016/s0040-4020(01)91019-1
日期:1991.9
The problem of achieving reaction selectivity in -alkyl vinylcyclopropanes in favour of their rearrangement to cyclopentenes, obviating the competing low energy process of the [1,5] (homo) sigmatropic hydrogen shift, is addressed. It has been demonstrated that the readily available bicyclo[4.1.0]heptenes derived from (+)-Δ3-carene. (1), upon photosensitized irradiation, are conveniently transformed
A procedure was developed for the stereoselective synthesis of aminated derivatives of (+)-1-(1R,3R,6S)-4,7,7-trimethylbicyclo[4.1.0]hept-4-en-3-yl}ethan-1-one. The configuration of the sidechain chiral center in (+)-1-(1R,3R,6S)-4,7,7-trimethylbicyclo[4.1.0]hept-4-en-3-yl}ethan-1-ol was determined by X-ray analysis. Diketene and Meldrum's acid were proposed as initial compounds for the synthesis of, respectively, 3-oxobutanoic and malonic acid esters having a 1-ethyl-4,7,7-trimethylbicyclo[4.1.0]hept-4-ene fragment.