No abstract

An efficient procedure is described that leads to pure (SP)‐O‐l‐menthylphenylthiophosphinate. The absolute configuration of this diastereomer was assigned by chemical correlation and confirmed by X‐ray crystallography. The reaction of the isomer with phenyl azide, leading to amidate, is a new variant of the stereoselective Staudinger reaction. Addition of elemental selenium to the (SP)‐thiophosphinate led to diastereomeric O‐l‐menthylphenylselenophosphonothioic acid, which was finally oxidized to the diastereomeric (RP1,RP2)‐bis‐[O‐l‐menthylphenylphosphonothionyl] diselenide. The diselenide structure was unambiguously confirmed by 31P NMR spectroscopy.

iodine-water oxidation of compound 1, condensation of 1 with (R),-7 together with the reaction of the latter with trimethylsiiyl azide results in the formation of stable (S),,(S),-Z.In an earlier paper we reported the synthesis of ( R ) , and (S), compounds R(R'O)P(S)SCl 3 (R = L-menthoxy, R' = ethyl).' These compounds are closely related to the disulphides [R(R'O)P(S)SI2 2. Both types of compounds have a strongly electrophilic sulphur atom attached to a good leaving group which gives them properties similar to pseudohalogen species .2Recently, we have found an unusual case of stereoselectivity leading to the pure disulphide 2 having (S), configuration on both phosphorus atoms. This disulphide was prepared in

4-Hydroxybenzoate oligoprenyl transferase from E. coli (ubiA-prenyl transferase) is a crucial enzyme for ubiquinone biosynthesis. It catalyzes the formation of 3-oligoprenyl-4-hydroxybenzoates like geranyl hydroxybenzoate (GHB, 23) from geranyl pyrophosphate (GPP, 22). Several analogues and mimics of geranyl pyrophosphate have been prepared for an examination of their ability to inhibit the enzyme. 7,11-Dimethyl-3-oxododeca-6,10-dienoic acid (2), 3-hydroxy-7,11-dimethyldodeca-6,10-dienoic acid (3), 2-hydroxy-4,8-dimethyl-3,7-nonadienylphosphonic acid (4), and tripotassium [[(4E)-5,9-dimethyldeca-4,8-dienyl]phosphinato](difluoro)methylphosphonate (5) were synthesized from geraniol. ω-2,ω-1-Dihydroxylated farnesyl diphosphate 6 was prepared from trans,trans-farnesol. All compounds were tested for enzyme inhibition in a competitive assay with natural substrate. The effect of these compounds on ubiA-prenyltransferase activity varied substantially, ranging from almost full inhibition to, surprisingly, enhanced enzymatic activity at low concentrations by some compounds. A special, EDTAmodifyable magnesium effect is discussed as potential reason.