Synthesis of allenylzinc reagents by 1,2-rearrangement of alkynyl(disilyl)zincates derived from acetylenic epoxides and acetylenic aziridines - 22/05/17
Abstract |
Lithium alkynyl(disilyl)zincates obtained from metalated ethynyloxiranes, as well as from N-tert-butanesulfinyl(ethynyl)aziridines or N-tert-butanesulfonyl(ethynyl)aziridines, undergo 1,2-migration of the organosilyl group with ring opening of the oxirane or aziridine ring by SNi displacement. A developed protocol that involves nBuLi for the metalation step offers a straightforward approach to the corresponding δ-oxy- and δ-amino α-silyl allenylzinc intermediates. The reagents derived from the epoxides are amenable to subsequent in situ condensation with aldehydes or ketones to provide 1,3-diols but not those derived from aziridines that only react sluggishly in similar condensations.
Le texte complet de cet article est disponible en PDF.Keywords : Alkynes, Carbenoids, Rearrangement, Silicon, Zinc
Plan
Vol 20 - N° 6
P. 609-616 - juin 2017 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.