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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 S N i displacement. A developed protocol that involves n BuLi 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.

International audience; Conjugate addition of lithium enolates onto terminal alkynyl- and allenyl-sulfoxides furnishes the corresponding allylic sulfoxides. The latter readily undergo a Mislow-Braverman-Evans rearrangement to yield the targeted α-keto vinyl carbinols. This two-step procedure does not require purification of the intermediates and constitutes the shortest approach to α-keto vinyl carbinols.

International audience; A new radical addition/C-C bond fragmentation process is reported. Vinyl carbinols derived from 2-methyl-2-phenylpropanal react with radicals generated from xanthates to give the corresponding ketones. The radical cleavage reaction proceeds under mild conditions, in good to high yield, and in the presence of the unprotected carbinol. Highly functionalized 1,5-diketones and pyridines are readily available using this approach.

International audience; A modular, convergent, and operationally simple route to trifluoromethyl alkenes and vinyl fluorides involving a unique carbon-oxygen bond homolysis is reported. Highly functionalized trifluoromethyl alkenes and vinyl fluorides were obtained in good yields and good selectivity.