Ketones Julia-Lythgoe olefination

Marko, I. E., Murphy, F., Kumps, L., Ates, A., Touillaux, R., Craig, D., Carballares, S., Dolan, S. Efficient preparation of trisubstituted alkenes using the Sml2 modification of the Julia-Lythgoe olefination of ketones and aldehydes. Tetrahedron 2001,57, 2609-2619. 

The olefination of ketones to prepare trisubstituted alkenes employing Na-Hg affords moderate yields, unpredictable stereoselectivities and large amounts of retro-aldol products from the intermediate jS-alkoxy sulfones. High yields and moderate stereoselectivities of trisubstituted alkenes are obtained by a modification of the Julia-Lythgoe olefination reaction, involving the in situ capture of the intermediate y6-alkoxy sulfones with a... 

Modification of the Julia-Lythgoe olefination reaction between ketones and primary sulfones leads to trisubstituted alkenes in good overall yields reported by Marko and co-workers. Samarium diiodide/HMPA shown to play a crucial role in the reductive elimination step. Starting from sulfone 40, key intermediate 42 was produced in 93% yield, which was further converted to 43 in 73% yield with E/Z ratio of 2 1. More complicated intermediate 44 was similarly reduced by Smh to 45 in 68% yield. 

Marko IE, Murphy F, Dolan S. Efficient preparation of tri-substituted alkenes using the Julia-Lythgoe olefination of ketones. On the key-role of Sml2 in the reductive ehmination step. Tetrahedron Lett. 1996 37(12) 2089-2092. 

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