Versatility in the Brook Rearrangement for the Selective Ring-Opening of Three-Membered Rings.

From a single α-silylated carbinol intermediate, easily accessible by carbometallation of cyclopropenes, various scaffolds featuring a quaternary carbon stereocenter could be obtained selectively. The selectivity towards these different products was achieved by either changing the experimental conditions or the nature of the organometallic species involved.

Facile and chemoselective rhodium-catalysed intramolecular hydroacylation of α,α-disubstituted 4-alkylidenecyclopropanals.

Mild intramolecular hydroacylation of α,α-disubstituted 4-alkylidenecyclopropanals has been developed, avoiding decarbonylation and affording cycloheptenones in good yields. The reaction is chemoselective in favour of the alkylidenecyclopropane moiety when potential alkene or alkyne acceptors are tethered to the substrate.