Stereochemistry at secondary carbon in organometallic insertion reactions

The stereochemistry of insertion reactions occurring at secondary carbon atoms bound to transition metals has been probed by examination of 13C and 1H spectra of 1,4-disubstituted cyclohexyl systems. The reaction of neat sulfur dioxide with cis and trans -4-methylcyclohexyl (pyridine)-cobaloxime leads to the trans and cis -4-methylcyclohexyl-S-sulfinate cobaloximes respectively, indicating inversion of configuration at the reacting carbon atom. A similar inversion is observed in the reaction of sulfur dioxide with [cis-4-methylcyclohexyl Fe(CO)2(η5-C5H5)], but the triphenylphosphine-induced insertion of carbon monoxide in acetonitrile proceeds with retention of configuration

Substituent effects in dimethylsulfoxide-promoted carbon monoxide insertion into iron-alkyl bonds

The insertion reaction of carbon monoxide, induced by dimethylsulfoxide, into iron-carbon sigma bonds in the complexes, [(η5-C5H5)(CO)2-FeR], has been extended to a wide variety of primary and secondary alkyl substituents. Rate constants for the forward (k1) and reverse (k-1) reactions, together with the second order rate constant (k2), for the further reaction of the solvated acyl complex with triphenylphosphine, have been measured and evaluated. The major substituent effect is seen in k1 and appears largely to reflect steric enhancement of reaction. The relative reactivity of a series (methyl through n-octyl) of straight chain alkyl complexes has been compared with a recent theoretical prediction. Thermodynamic and kinetic parameters for the formation of the solvated acyl have been measured and evaluated

Alkyl substituent effects in ligand-induced carbon monoxide insertion reactions in [(η5-C5H5)(CO)3Mo(benzyl)] systems

The first order reactions of benzyl-molybdenum complexes, [(η5-C5H5)(CO)3Mo(CH2C6H4X)], with triphenylphosphine in acetonitrile to yield the trans-substituted acyl complexes, [(η-C5H5)(CO)2(PPh3)Mo(COCH2C6H4X)], have an overallrate constant which tends towards a limiting value at high triphenylphosphine concentration. The reactivity of the molybdenum-carbon bond is enhanced by electron donating substituents, X, and can be analysed in terms of Hammett substituent parameters. A marked enhancement of rate is observed in dimethylsulfoxide, in which solvent the cis-acyl complex is the unexpected initial product

A critical exploration of lesbian perspectives on eating disorders

There is now a considerable body of research exploring how culturally dominant gendered norms are implicated in mobilising girls' and women's 'anorexic' and 'bulimic' experiences and practices. However, much less is known about lesbian experiences of 'eating disorders'. This article explores some of those specificities. Drawing on interviews with self-identified lesbian women with a history of 'anorexia' and/or 'bulimia', our analysis suggests that while many of the ways in which participants discursively constituted their 'eating disorders' were similar to those identified in research with girls and women assumed to be heterosexual, there were also important differences where participants' actual or emerging lesbian subjectivities were integral to their accounts of developing, living with and recovering from 'anorexia' and/or 'bulimia'. Our analysis suggests that the processes of coming to recognise oneself as a lesbian and of 'coming out' to others in predominantly hetero-normative contexts may be profoundly implicated in the discursive production of lesbian women's 'eating disorders' and that further research is required to better understand lesbian perspectives on 'eating disorders'. © 2013 Copyright Taylor and Francis Group, LLC