ol8b03705_si_001.pdf (8.52 MB)
Domino Synthesis of Benzo-Fused β,γ-Unsaturated Ketones from Alkenylboronic Acids and N‑Tosylhydrazone-Tethered Benzonitriles
journal contribution
posted on 2019-01-14, 12:48 authored by Manuel Plaza, Miguel Paraja, Lucía Florentino, Carlos ValdésThe transition-metal-free domino
reaction between alkenylboronic
acids and N-tosylhydrazones from o-(2-oxoalkyl)- and o-(3-oxoalkyl)benzonitriles leads
to β,γ-unsaturated indanones and tetralones featuring
an α-“all-carbon” quaternary center. The employment
of derivatives of α-substituted cyclopentanones and cyclohexanones
led to the stereoselective preparation of β,γ-unsaturated
tetrahydrocyclopenta[a]inden-8(1H)-ones, hexahydrofluorenones, and hexahydroanthracenones
as cis-fused single stereoisomers. A domino sequence
involving diazo compound formation/reductive alkenylation/1,3-borotropic
rearrangement/intramolecular bora-aza-ene reaction is proposed to
justify the formation of the products as well as the stereoselectivity.