process that stereoselectively led to bi- and tricyclic compounds in moderate to excellent yields. Four X-raycrystalstructure analyses unequivocally defined the structure of crucial cyclization products. The relative configuration of the precursor compounds is essentially transferred to that of the products and the formed hydroxy group in the newly generated cyclohexane ring is consistently in trans-arrangement
Highly substituted benzannulated cyclooctanol derivatives by samarium diiodide-induced cyclizations
作者:Jakub Saadi、Irene Brüdgam、Hans-Ulrich Reissig
DOI:10.3762/bjoc.6.141
日期:——
This systematic study reveals that steric and electronic factors exhibited by the alkene and ketone subunits are of high importance for the outcome of these cyclization reactions leading to highly substituted benzannulated cyclooctanol derivatives. In exceptional cases, 7-exo-trig cyclizations to cycloheptanol derivatives have been observed. In examples with high steric hindrance the ketyl-aryl coupling
A novel rearrangement leading to methoxycarbonylmethylated silyl enol ethers
作者:Hans-Ulrich Reissig
DOI:10.1016/s0040-4039(00)98693-3
日期:1985.1
Methyl 2-siloxycyclopropanecarboxylates rearrange smoothly and quantitatively to the corresponding silylenolethers (3) by addition of a catalytical amount of iodo trimethylsilane. Scope and limitation of this novelprocess as well as the synthesis of the electron rich diene (10a) are described.
Low temperature equilibration of cyclopropanes by Lewis acid catalysis
作者:Hans-Ulrich Reissig、Ingrid Böhm
DOI:10.1016/s0040-4039(00)81506-3
日期:1983.1
Under the influence of Lewis acids the cis/trans-equilibration of methyl 2-trimethyl-siloxy cyclopropanecarboxylates occurs even at −78°C. It involves the heterolytic cleavage of a CC bond and seems to be governed by steric effects.