The use of aqueous acidic conditions for the preparation of arylsulfonyl chlorides from diazonium salts in the presence of copper salts, preferably CuCl, together with thionyl chloride as the sulfur dioxide source, has considerable advantages over recommended literature procedures, whereby reactions are carried out in acetic acid with minimisation of water content of the solvent. The method has been shown to be successful for a wide range of electron-deficient and electron-neutral aryl substrates. The sulfonyl chlorides are protected from hydrolysis by their low solubility in water, which results in their direct precipitation from the reaction mixture in good yields (>70%) and high strength (>98% w/w). The aqueous process, which is additionally safer and more robust, can be readily scaled up and has significant environmental benefits.

The enantioselective reduction of racemic sulfoxides by dimethyl sulfoxide reductases from Rhodobacter capsulatus, Escherichia coli, Proteus mirabilis and Proteus vulgaris was investigated. Purified dimethyl sulfoxide reductase from Rhodobacter capsulatus catalysed the selective removal of (S)-methyl p-tolyl sulfoxide from a racemic mixture of methyl p-tolyl sulfoxide and resulted in an 88 O/ o recovery of enantiomerically pure (R)-methyl pltolyl sulfoxide. Rhodobacter capsulatus was shown to be able to grow photoheterotrophically in the presence of certain chiral sulfoxides under conditions where a sulfoxide is needed as an electron sink. Whole cells of Rhodobacter capsulatus were shown to catalyse the enantioselective reduction of methyl p-tolyl sulfoxide, ethyl 2-pyridyl sulfoxide, methylthiomethyl methyl sulfoxide and methoxymethyl phenyl sulfoxide. Similarly, whole cells of Escherichia coli, Proteus mirabilis and Proteus vulgaris reduced these sulfoxides but with opposite enantioselectivity.

The development of a commercial manufacturing process for fulvestrant (the active ingredient in 'Faslodex') is described. Key steps in the synthesis are stereoselective 1,6-addition of an organocuprate to a steroidal dienone followed by copper-mediated aromatisation of the A-ring. The strategy for dealing with noncrystalline intermediates is outlined. The production of drug substance of acceptable quality is critically dependent on limiting the formation of key impurities. The origin of these impurities is discussed, and measures to prevent or control their formation are described.

Chiral amines are one of the ubiquitous functional groups in fine chemical, pharmaceutical and agrochemical products, and the most convenient, economical, and eco-benign synthetic pathway to these amines is direct asymmetric reductive amination (DARA) of prochiral ketones. This paper shows that a wide range of aliphatic ketones can be directly aminated under hydrogenation conditions, affording chiral amines with good to excellent yields and with enantioselectivities up to 96% ee. The catalysis is effected by the cooperative action of a cationic Cp*Ir(III) complex and its phosphate counteranion.

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