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4-Acetoxy-l-(trimethylsilyl)azetidin-2-one reacted smoothly with the silyl enol ethers [R1CH==C(OSiMe3)R2] [R1 = H, Me; R2 = Ph, C6H4-4-Cl, C6H4-4-Me, SPh, OCH2Ph, OEt, CH=C(OMe)OSiMe3] in dichloromethane solution in the presence of trimethylsilyl trifluoromethanesulfonate as catalyst to produce the corresponding a-(2-oxoazetidin-4-yl) esters and ketones. Attempts to intercept l-azetin-4-one, the intermediate in the nucleophilic displacement reactions of 4-acetoxyazetidin-2-one, with dienes were unsuccessful.Thienamycin (1) (Chart I) is a third generation /3-lactam antibiotic produced by Streptomyces cattylea.1 On account of its excellent broad spectrum activity, 1 and structurally related carbapenems have been the subject of extensive synthetic investigations.2 Prior to these studies, Clauss and co-workers at Hoechst described the chemistry of a versatile /3-lactam: 4-acetoxyazetidin-2-one (2a).3 Acetate 2a was prepared via the cycloaddition reaction of chlorosulfonyl isocyanate with vinyl acetate. On reaction with diverse oxygen-, nitrogen-, and sulfur-centered nucleophiles, 2a was found to produce the corresponding C-4 substitution products. For example, on reaction with 2a, magnesium methoxide, sodium phenoxide, azide, and O-ethyl xanthate gave 2b, 2c, 2d, and 2e, respectively.Clauss also noted that the nucleophilic displacement reaction proceeded with racemization. Thus it is possible

The development of a pilot plant process to prepare the spirocyclic piperidine (2) from the tetrahydropyridine (4) via a radical cyclisation reaction is described. The pilot plant process involves the use of a catalytic amount of tributyltin hydride (0.14 equiv) generated in situ by the reaction of tributyltin chloride with sodium borohydride (1.1 equiv) in 2-propanol/ethanol containing azo-bis(isobutyronitrile) (AIBN). Initial laboratory conditions are described as well as the changes made on transfer to the pilot plant. Measurement of the levels of residual amounts of tin in the batches of (2) produced are reported.

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The first total synthesis of an important C13 butyl rubber oligomer is reported. The structure of the oligomer, which is an important and potentially toxic extractable and leachable component of elastomeric closures, is confirmed by synthesis for the first time. The method described is scalable, making large quantities of the oligomer available for the first time for AMES toxicity studies. The challenging synthesis commences with isophorone and the key steps of the synthesis involve the development of highly novel dithoacetal chemistry, cuprate addition and Tebbe olefination.