M. Mahmun Hossain

Iron mediated nitrenoid transfer: [(η5-C5H5)Fe(CO)2(THF)]+[BF4]− catalyzed aziridination of olefins

Abstract The iron Lewis acid catalyst, [(η5-C5H5)Fe(CO)2(THF)]+[BF4]−, has previously been found to catalyze a growing array of synthetic transformations. Building upon these precedents, the utility of the catalyst has now been extended to catalytic reaction involving olefins and (N-(p-tosyl)imino)phenyliodinane, PhI=NTs, which serves as a nitrenoid precursor, to produce aziridines with yields up to 85%.

The synthesis of S-(+)-2,2-dimethylcyclopropane carboxylic acid: a precursor for cilastatin

Abstract S -(+)-2,2-Dimethylcyclopropane carboxylic acid, a precursor for cilastatin, was prepared from 2-methylpropene and chiral iron carbene in three steps. Asymmetric cyclopropanation reaction of 2-methylpropene with iron carbene complex having chirality at the carbene ligand, followed by exhaustive ozonolysis, produced S -(+)-2,2-dimethylcyclopropanecarboxylic acid of up to 92% ee. The absolute configuration of complexed chiral cyclopropane (−)- 8 was determined by X-ray crystallographic analysis.

IRON LEWIS ACID CATALYZED REACTIONS OF PHENYLDIAZOMETHANE WITH AROMATIC ALDEHYDES

Abstract The iron Lewis acid 1 was found to catalyze reactions of phenyldiazomethane and aromatic aldehydes to give cis -epoxides along with the corresponding ketones. The yield of the epoxide increased with electron-withdrawing substituents on the aldehyde, while little or no epoxide was formed with electron-donating substituents. The reaction was found to go through the coordination of the aldehyde to the iron Lewis acid instead of a carbene intermediate.

Iron Lewis acid catalyzed reactions of phenyldiazomethane and olefins: Formation of cyclopropanes with very high cis selectivity

Abstract The iron Lewis acid, [(η 5 -C 5 H 5 )Fe(CO) 2 (THF)] + ( 1 ) catalyzes the cyclopropanation reaction of phenyldiazomethane with olefins to provide cis cyclopropanes in high selectivity.

Selective isomerization of aryl substituted epoxides to aldehydes via iron Lewis acid catalysis

The iron Lewis acid [(η5-C5H5)Fe(CO)2(THF)]+BF4− (2) catalyzes the ring opening isomerization of aryl substituted epoxides (1) to aldehydes (3) in excellent yield.

Iron Lewis acid catalyzed reactions of ethyldiazoacetate with styrene and α-methylstyrene: Formation of cyclopropanes with cis selectivity

Abstract The iron Lewis acid, (η5-C5H5)Fe+(CO)2(THF)BF4− catalyzes the reaction of ethyldiazoacetate with styrene and α-methylstyrene to provide cyclopropanes with a preference for the cis isomer.

Transition metal catalysis of the diels-alder reaction

Catalysis of the Diels-Alder reaction by the transition metal Lewis acid, (n5-C5H5)Fe+(CO)[P(OCH3)3](THF)BF4−, is reported.

Asymmetric cyclopropanation reactions via iron carbene complexes having chirality at the carbene ligand

The reaction of Fp [(η5-C5H5)Fe(CO)2] anion (1) with chiral (+) or (−) o-anisaldehyde(tricarbonyl)chromium (2) in the presence of chlorotrimethylsilane produced the optically pure (+) or (−) bimetallic complex 4. Separate treatment of 4 at −78° C with trimethylsilyltriflate in the presence of styrene, followed by decomplexation with iodine, produced the corresponding cyclopropanes (101, cistrans). A 60% ee was indicated for the cis cyclopropanes.

Solvent Extraction Separation of Trivalent Americium from Curium and the Lanthanides

The sterically constrained, macrocyclic, aqueous soluble ligand N,N′-bis[(6-carboxy-2-pyridyl)methyl]-1,10-diaza-18-crown-6 (H2BP18C6) was investigated for separating americium from curium and all the lanthanides by solvent extraction. Pairing H2BP18C6, which favors complexation of larger f-element cations, with acidic organophosphorus extractants that favor extraction of smaller f-element cations, such as bis-(2-ethylhexyl)phosphoric acid (HDEHP) or (2-ethylhexyl)phosphonic acid mono(2-ethylhexyl) ester (HEH[EHP]), created solvent extraction systems with good Cm/Am selectivity, excellent trans-lanthanide selectivity (Kex,Lu/Kex,La = 108), but poor selectivity for Am against the lightest lanthanides. However, using an organic phase containing both a neutral extractant, N,N,N’,N’-tetra(2-ethylhexyl)diglycolamide (TEHDGA), and HEH[EHP] enabled rejection of the lightest lanthanides during loading of the organic phase from aqueous nitric acid, eliminating their interference in the americium stripping stages. In addition, although it is a macrocyclic ligand, H2BP18C6 does not significantly impede the mass transfer kinetics of the HDEHP solvent extraction system.

An explanation for the apparent cis-aziridine selectivity in the iron Lewis acid-catalyzed reaction of N-benzylidene aniline and ethyl diazoacetate

Abstract The reason for the apparent cis -aziridine selectivity in the reaction of ethyl diazoacetate with N -benzylidene aniline, catalyzed by [(η 5 -C 5 H 5 )(CO) 2 Fe(THF)] + [BF 4 ] − , is reported. The catalytic reaction produces both cis and trans -aziridines. Once the imine has been consumed, the trans -isomer is shown to undergo a catalytic decomposition, leaving cis -aziridine and by-products. The reaction is graphically profiled to illustrate the relative quantity of reactants and products as a function of time. A new mechanistic model is proposed in order to explain the observed selectivity.