Heteroarylsulfones Julia olefinations

In the Kocienski-modified Julia olefination, replacement of the phenylsulfone moiety with a heteroarylsulfone such as the 1-phenyl-l/T-tetrazol-5-yl group (PT), shown below, profoundly alters the course of the Julia coupling. The olefin product is obtained in a one-pot procedure as opposed to the three-step protocol of the classical Julia olefination. ... 

Generation of Sulfur Ylides Julia Olefination and Related Processes. Recently, the modified Julia olefination, which employed certain heteroarylsulfones instead of the traditional phenyl-sulfones, has emerged as a powerful tool for alkene synthesis. Although the reaction was first reported with LDA, bases such as LHMDS, NaHMDS, and KHMDS are now commonly used. In addition, solvent as well as base counter-cation have been shown to markedly affect the stereochemical outcome of the olefination reaction. For instance, KHMDS was less selective than NaHMDS for the coupling between benzothiazoylsulfone (1) and cyclopropane carboxaldehyde (2) in toluene, furnishing a 3.7 1 ratio compared to a 10 1 ratio favoring the Z-isomer. However, both bases provided a 1 1 mixture of isomers when the reaction was run in DMF (eq 54). ... 

More recently, the modified Julia olefination, which employed certain heteroarylsulfones instead of the traditional phenylsul-fones, has emerged as a powerful tool for alkene synthesis. Although the reaction was first reported with LDA, bases such... 

Modified one-port Julia-Lythgoe olefination to give predominantly ( )-olefins from heteroarylsulfones 4 and aldehydes is called as Julia-... 

The synthesis of , Z-dienes, 79 and 80, was developed by Charette and co-workers from a,y9-unsaturated aldehydes, 77, and heteroarylsulfones, 78, using the Julia-Lythgoe olefination reaction. The selectivity of the olefination reaction under optimal conditions is better than 88 12 when a pyridylsuofone was used as the precursor. 

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