Metalation of o-methylanisole (o-MA); an optional-site selectivity reassessment
作者:D.W. Slocum、Sophia Wang、Christopher B. White、Paul E. Whitley
DOI:10.1016/j.tet.2010.05.036
日期:2010.7
'Deficiency catalysis' is the concept applied to metalation chemistry that increments of TMEDA or an equivalent or two of an ether activate alkyllithiums in hydrocarbon media. Amplification of this concept to conflicting reports of alpha- and ortho-metalation of ortho-methylanisole (o-MA) is explored. Both regioselective metalations were realized in selectivity ratios of >7:1 for the desired isomers. Some rationale is provided for the various selectivities. These results are at variance with prior results and interpretations thereof found in the literature. (C) 2010 Elsevier Ltd. All rights reserved.