of allylic derivatives by the siloxanes D4H and MDHM
in the presence of platinum catalysts
A. El Malki1, A. Hannioui1, N. Knouzi2*, M. Vaultier3
1Université Cadi Ayyad, FST Béni-Mellal, B.P.523 Béni-Mellal. Maroc.
2Université Hassan II, Faculté Des Sciences Sidi Othmane, BP6023, Casablanca, Maroc.
3Laboratoire de Synthèse et Electrosynthèse Organiques UMR 6510,Université Rennes I,. France.
* Corresponding author. E-mail : email@example.com
Received : 28 December 2002; revised version accepted : 19 December 2003
New functionalized cyclic and acyclic siloxanes have been prepared in high yields by the platinum catalyzed hydrosilylation of terminal alkenes functionalized in the allylic positions. Conditions have been found that allow the regioselective obtention of siloxanes resulting exclusively from a b -addition of D4H or MDHM to the double bond. This regioselectivity depend on several factors including solvent, catalyst, amount of catalyst, reaction temperature and order of addition of reactants. The optimized conditions are compatible with the presence of free alcohol groups thus allowing the direct preparation of functionalized siloxanes. All new compounds were characterized by 1H, 13C, 29Si NMR and HRMS as well.
Keywords: Hydrosilylation; Platinum catalysts; Terminal olefins; Functionalized siloxanes; Regioselectivity.