Goeran Hilmersson

Instantaneous Deprotection of Tosylamides and Esters with SmI2/Amine/Water

SmI(2)/amine/water mediates instantaneous cleavage of tosyl amides and tosyl esters. Highly hindered, sensitive and functionalized substrates were successfully deprotected in near quantitative yield.

Selective reduction of carboncarbon double and triple bonds in conjugated olefins mediated by SmI2/H2O/amine in THF

Conjugated double and triple bonds are reduced into alkenes using non-hazardous SmI2/H2O/amine mixtures as reducing agents in THF. Isolated alkenes are not reduced during these reductions. All the reactions studied are quantitative and are completed in less than five minutes.

Asymmetric addition of n-butyllithium to aldehydes: new insights into the reactivity and enantioselectivity of the chiral amino ether accelerated reaction

Enantioselective butylation of benzaldehyde with n-butyllithium was mediated by a series of chiral lithium amide analogues to give 1-phenylpentanol in good to moderate enantioselectivities. In order to achieve high enantiomeric excess in the reaction, the lithium amide must have a substituent larger than methyl on both the carbon at the stereogenic center and the nitrogen. Computational studies, using semi-empirical (PM3) and density functional (B3LYP) methods, show that the stabilities of the transition states for the chiral lithium amide accelerated butylation of isobutyraldehyde are in agreement with experiments.

Chiral lithium amido sulfide ligands for asymmetric addition reactions of alkyllithium reagents to aldehydes

Six chiral amino sulfides have been synthesised from the amino acids phenylalanine, phenylglycine and valine. These amino sulfides were used as chiral ligands in the asymmetric addition of n-butyllithium and metyllithium to various aldehydes at low temperatures. The highest stereoselectivities were obtained with benzaldehyde, resulting in 1-phenyl-1-pentanol and 1-phenyl-1-ethanol in enantiomeric excesses of >98.5 and 95%, respectively. These stereoselectivities were significantly higher than those induced by the ether analogues.

Selective α-defluorination of polyfluorinated esters and amides using SmI2/Et3N/H2O

SmI(2)/H(2)O promotes selective α-monodefluorinations, while addition of an amine results in complete α-defluorination reactions.