23009-74-7Relevant academic research and scientific papers
The Influence of Chain-branching on the Steric Outcome of Some Olefin-forming Reactions
Kocienski, Philip J.,Lythgoe, Basil,Waterhouse, Ian
, p. 1045 - 1050 (2007/10/02)
When applied to the construction of internal disubstituted double bonds in compounds such as pentadec-7-ene and 2,6,11,15-tetramethylhexadeca-2,6,8,10,14-pentaene (5), the reductive elimination of vicinal benzoyloxy-sulphones gives products with a trans:cis ratio of ca. 4:1.When applied to the construction of disubstituted olefins in which branching occurs adjacent to the newly formed double bond, much higher trans-stereoselectivity is observed, e.g. for 5-ethyl-2-methylhept-3-ene (21) and 3,6-dimethylocta-2,4,6-triene (25) it is at least 98percent.A similar effect of chain-branching is also observed in some Wittig and Horner reactions using primary allylic phosphorus derivatives.When a Z-allylic sulphone is used as the starting material in the benzoyloxy-sulphone method, the original Z-geometry is preserved in the product; (Z)-2-methylbut-2-enyl p-tolyl sulphone and tiglic aldehyde give almost exclusively (2E,4E,6Z)-3,6-dimethylocta-2,4,6-triene (27).
