Shape selective alkane hydroxylation by metalloporphyrin catalysts

Journal Article · Tue Nov 11 23:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00283a024· OSTI ID:7129836

Cook, B R; Reinert, T J; Suslick, K S

A series of manganese and iron porphyrins with sterically protected pockets are shown to be shape selective alkane hydroxylation catalysts. With iodosobenzene as oxidant, good regioselectivity is observed for hydroxylation of alkanes at the least hindered methyl group by using the very sterically hindered (5,10,15,20-tetrakis(2',4',6'-triphenylphenyl)-porphyrinato)manganese(III) acetate (MnTTPPP(OAc)) as catalyst; the moderately hindered (5,10,15,20-tetrakis(2',4',6'-trimethoxyphenyl)porphyrinato)manganese(III) acetate shows little selectivity toward terminal CH/sub 3/ hydroxylation but does show enhancement for the adjacent, omega-1, CH/sub 2/ site. Primary selectivity is dependent on the size and shape of the alkane substrate, with more bulky substituents giving greater primary selectivity. Substituting pentafluoroiodosobenzene or m-chloroperbenzoic acid as oxidants yields similar selectivity, thus conclusively demonstrating metal based oxidation via a common intermediate for these three systems. In contrast, tert-butyl hydroperoxide or 2,2,2-trifluoroethanol solubilized pentafluoroiodosobenzene show no primary carbon selectivity, and reaction product ratios are independent of the metalloporphyrin catalyst; this demonstrates that the site of oxidation with these oxidants is not metal based. The iron porphyrin derivatives also show good primary selectivity, although to a lesser degree than with the Mn derivatives, proving that these oxidations too are metal based.

• Research Organization: Univ. of Illinois, Urbana-Champaign
• OSTI ID: 7129836
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:23; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACETATES
ALKANES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION YIELD
COMPLEXES
DATA
EXPERIMENTAL DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROXYLATION
INFORMATION
IRON COMPLEXES
MANGANESE COMPLEXES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PORPHYRINS
STEREOCHEMISTRY
TRANSITION ELEMENT COMPLEXES
YIELDS