Beilstein J. Org. Chem.2006,2, No. 16, doi:10.1186/1860-5397-2-16
, DIBAH) occurs normally by 1,2-attack, this being a key step in the well known "carbonyl transposition" of 1,3-diketone enol ethers into enones (R3O-CR=CR1-COR2 → R-CO-CR1=CHR2). [11][12][13][14][15] Prior to our work there were no reports on the reduction of isoflavones containing free hydroxy groups
Beilstein J. Org. Chem.2005,1, No. 11, doi:10.1186/1860-5397-1-11
conjugate addition of nitroalkanes to α,β-unsaturated ketones 1 leading to the nitroalkanes derivatives 2 which may be converted into their γ-diketone homologues 3 using Nef reaction. The intramolecular cyclization of 1,4-diketones 3 led to the corresponding cyclopentenones 4.
Results and discussion
As
C9H14O4: 186.0892. Found: 186.0877.
Preparation of γ-functionalized cyclopentenones (4): General procedure
To a solution of 1,4-diketone 3 (5 mmol) in MeOH (10 mL) was added 1 equivalent of K2CO3, the mixture was bring to reflux during one hour. After workup, the product 4 was purified by column
PDF
Graphical Abstract
Scheme 1:
Synthesis of nitroalkanes derivatives 2 and their corresponding 1,4-diketones 3.