𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Large rate accelerations in aldol reaction of ortho-substituted benzaldehydes

✍ Scribed by Goutam Das; Edward R. Thornton

Book ID
104225288
Publisher
Elsevier Science
Year
1991
Tongue
French
Weight
385 KB
Volume
32
Category
Article
ISSN
0040-4039

No coin nor oath required. For personal study only.

✦ Synopsis

The relanve reactivrtles of ortho-andpara-substituted benzaldehydes wrth the a5butylboron enolate of prnacolone have very dzfferent subsrrtuent dependences ortho subsmmts give large rate enhancements wrth electronreleasmg substituents. wlule para subsntuents gave extremely small rate effects Since chelation is lnaccesstble to the boron enolate (which must also complex to the aldehyde). the orrgrn of the large ortho effects was inveshgated by

πŸ“œ SIMILAR VOLUMES

Co-operative ortho-effects on the Wittig
Co-operative ortho-effects on the Wittig reaction. Interpretation of stereoselectivity in the reaction of ortho-halo-substituted benzaldehydes and benzylidenetriphenylphosphoranes
✍ Eoin C Dunne; Γ‰amonn J Coyne; Peter B Crowley; Declan G Gilheany πŸ“‚ Article πŸ“… 2002 πŸ› Elsevier Science 🌐 French βš– 87 KB

The E/Z ratios of the stilbenes 1 formed in the Wittig reaction of ortho-halo substituted benzyltriphenylphosphonium salts 2 and benzaldehydes 3 were determined. It was found that there is a co-operative effect of one ortho-halo group on each of the two reacting partners which increases Z-selectivit