Influence of different protecting groups on the regioselectivity of the hydrotelluration reaction of hydroxy alkynes
摘要:
The influence of protecting groups on the synthesis of regio- and stereodefined vinyl tellurides derived from the reaction of BuTeNa and propargylic- or homo-propargylic alcohols showed that TIPS silyl ether is useful as a regiodirecting group. The application of the methodology to the synthesis of a fragment of (+/-)-Seselidiol, a natural product, demonstrated the applicability of the new methodology.
All-Carbon Quaternary Centers via Ruthenium-Catalyzed Hydroxymethylation of 2-Substituted Butadienes Mediated by Formaldehyde: Beyond Hydroformylation
作者:Tomas Smejkal、Hoon Han、Bernhard Breit、Michael J. Krische
DOI:10.1021/ja904124b
日期:2009.8.5
Ruthenium-catalyzedtransferhydrogenation of 2-substituted dienes 1a-i in the presence of paraformaldehyde results in reductivecoupling at the 2-position to furnish the hydroxymethylation products 3a-i, which embody all-carbon quaternary centers. Reductivecoupling of diene 1g to paraformaldehyde under standard conditions, but employing deuterio-paraformaldehyde, 2-propanol-d(8), or both, corroborated