Use of cyclobutyl derivatives as intermediates in the synthesis of 1,2a,3,8b-tetrahydro-2H-cyclobuta[c]chromenes
作者:Angela M Bernard、Costantino Floris、Angelo Frongia、Pier P Piras、Francesco Secci
DOI:10.1016/j.tet.2003.11.018
日期:2004.1
Starting from cyclobutanones and tertiary cyclobutanols several new chromenes containing a cyclobutane ring have been prepared by acid catalyzed intramolecular alkylation of an oxygen-carrying aromatic ring. Interestingly one of the cyclobutanols leads to 3-[(4-methoxyphenoxy)methyl]-2,2,3-trimethylcyclopentanone that is a precursor in the synthesis of the carotenoid pigment capsorubin.
One Pot Synthesis of Cyclobutanols by Ring Expansion of Oxaspiropentanes Induced by Grignard Reagents
作者:Angela M. Bernard、Costantino Floris、Angelo Frongia、Pier P. Piras
DOI:10.1055/s-1998-1730
日期:1998.6
Aromatic, aliphatic and vinylic Grignard reagents efficiently catalyze the ring expansion of oxaspiropentanes 2 a,b to give, in one pot, good yields of cyclobutanols 3 a, 3 b - 7 b. Benzyl magnesium chloride gives a mixture of cyclobutanols and the cyclopropanol 8, probably coming from a direct nucleophilic attack on the epoxide part of the oxaspiropentane.
The First Facile Synthesis of Some 1,2a,3,8b-Tetrahydro-2H-Cyclobuta[c] Chromenes Through Intramolecular Alkylation of an Aromatic Ring by a Cyclobutanone
作者:Angela M. Bernard、Costantino Floris、Angelo Frongia、Pier P. Piras
DOI:10.1055/s-2002-25355
日期:——
Starting from cyclobutanones several new chromenes containing a cyclobutane ring are prepared. Ring fission of these derivatives gives easy access to functionalized 3-isoflavenes.