912552-09-1Relevant articles and documents
Dioxygenase-catalysed oxidation of disubstituted benzene substrates: Benzylic monohydroxylation versus aryl cis-dihydroxylation and the meta effect
Boyd, Derek R.,Sharma, Narain D.,Bowers, Nigel I.,Dalton, Howard,Garrett, Mark D.,Harrison, John S.,Sheldrake, Gary N.
, p. 3343 - 3349 (2008/09/16)
Biotransformations of a series of ortho-, meta- and para-substituted ethylbenzene and propylbenzene substrates have been carried out, using Pseudomonas putida UV4, a source of toluene dioxygenase (TDO). The ortho- and para-substituted alkylbenzene substrates yielded, exclusively, the corresponding enantiopure cis-dihydrodiols of the same absolute configuration. However, the meta isomers, generally, gave benzylic alcohol bioproducts, in addition to the cis-dihydrodiols (the meta effect). The benzylic alcohols were of identical (R) absolute configuration but enantiomeric excess values were variable. The similar (2R) absolute configurations of the cis-dihydrodiols are consistent with both the ethyl and propyl groups having dominant stereodirecting effects over the other substituents. The model used earlier, to predict the regio- and stereo-chemistry of cis-dihydrodiol bioproducts derived from substituted benzene substrates has been refined, to take account of non-symmetric subsituents like ethyl or propyl groups. The formation of benzylic hydroxylation products, from meta-substituted benzene substrates, without further cis-dihydroxylation to yield triols provides a further example of the meta effect during toluene dioxygenase-catalysed oxidations. The Royal Society of Chemistry 2006.
