Meso -Functionalized dipyrromethanes synthesis

In 2011, Singh et al. have reported the synthesis of meso-functionalized dipyrromethanes (11SC3491) 261 (X = NH) (Scheme 101) as well as unsym-metrical bis(heterocyclyl)methanes through Grignard addition of various aliphatic and aromatic halides on pyrrole-2-carboxaldehyde, followed by BF3 OEt2-catalyzed condensation of pyrrole-2-carbinols with pyrrole, etc. 

Scheme 101 Synthesis of meso-functionalized dipyrromethane through Grignard addition.

A simple and versatile one-pot synthesis of meso-substituted trans-A2B-corroles (Scheme 7) was reported by Gryko and Jadach (01JOC4267). It affords regioisomerically pure frans-A2B-corroles 11 through the TFA-catalyzed condensation of a dipyrromethane 10 and an aldehyde followed by oxidation with DDQ. The synthesis is compatible with diverse functionalities ester, nitrile, ether, fluoro, hydroxy, etc. on the aryl group of the... 

A variation of this method that removes the water produced in the pyrrole/aldehyde or hydrated aldehyde condensation has been used to produce meso-tetrakis(perfluoroalkyl)porphyrins. Lindsey s laboratory has also reported a rational synthesis of weyo-substituted porphyrins bearing one nitrogen heterocyclic group that can readily be used for preparing other mono-functionalized porphyrins, methods for minimi zing scrambling in the synthesisof tran -porphyrins from dipyrromethanes and aldehydes, and a rational synthesis of porphyrins bearing up to four different meso substituents. ... 

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See also in sourсe #XX -- [ ]

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