Iron Corrole-catalyzed [4 + 2] Cycloaddition of Dienes and Aldehydes
作者:Toru Kuwano、Takuya Kurahashi、Seijiro Matsubara
DOI:10.1246/cl.130672
日期:2013.10.5
We have developed cationic iron(IV) corrole-catalyzed formal hetero-Diels–Alder reaction of aldehydes with dienes, which opens the way for divergent synthesis of pyrans. The potential utility of the catalyst was also demonstrated by carrying out cycloaddition of α,β-unsaturated aldehyde with a diene to give pyran selectively. Furthermore, the catalytic reactivity of iron corrole complex on the cycloaddition was determined by comparing that of iron porphyrin complex.
strategy based on the heteroatom‐free tri‐atom donor to synthesize 3,6‐dihydro‐2H‐pyrans has been developed. In this method, 2‐arylpropylene served as tri‐atom donor to contribute three carbon atoms, the heteroatom was provided by aldehyde, and DMSO served as one carbon donor and solvent. This annulation reaction gave 3,6‐dihydro‐2H‐pyrans in moderate to good yields. Based on the control experiments, a
Cationic iron(III) porphyrin was found to be an efficient catalyst for the highly chemoselective hetero-Diels Alder-type reaction of aldehydes with 1,3-dienes. The catalyzed process did not require the use of electron-deficient aldehydes such as glyoxylic acid derivatives or activated electron-rich 1,3-dienes such as Danishefslcy's diene and Rawal's diene. The high functional group tolerance and robustness of the catalyst were demonstrated. Further, the potential utility of the catalyst was demonstrated by performing the cycloaddition in the presence of water and by carrying out cycloaddition of an unactivated ketone such as cyclohexanone with a diene.
AlCl3 catalyzed oxa-Diels-Alder reaction of aromatic aldehydes with simple dienes
作者:Wujun Jian、Bo Qian、Hongli Bao、Daliang Li
DOI:10.1016/j.tet.2016.10.049
日期:2017.7
A highly regioselective and diastereoselective oxa-Diels-Alder reaction catalyzed by AlCl3 has been developed. This reaction is efficient and characterized by good functional group compatibility, F, Cl, CN, NO2, OMe and thiophenyl groups are tolerated. A Lewis acid catalyzed concerted cycloaddition mechanism is proposed based on the results.