Pd(0)-Catalyzed Conjugate Addition of Benzylzinc Chlorides to α,β-Enones in an Atmosphere of Carbon Monoxide:  Preparation of 1,4-Diketones

Abstract

Pd(0)-catalyzed conjugate addition of benzylzinc chloride to methyl vinyl ketone in the presence of chlorotrimethylsilane and lithium chloride in an atmosphere of carbon monoxide at room temperature afforded 1-phenyl-2,5-hexanedione monosilyl enol ether. In this catalytic carbonylation, four components are connected in one reaction. Successive acidic workup generated a variety of 1,4-diketones from substituted benzylzinc chlorides or related compounds and alpha,beta-enones. Some products were converted to cyclopentenones or five-membered heterocyclic compounds containing an N, O, or S atom.

Synthesis of 2,5-diferrocenyl five-membered heterocyclic compounds and their electrochemistry

“…This one-pot cycloaddition synthesis could avoid low-temperature and multi-step procedures required by cross-coupling Negishi reactions. However, the yield of 6 is 5.7%, lower than Negishi reactions (62.1%) [26]. The possible reason of low yield could be ascribed to inefficient Pd(PPh 3 ) 3 Cl 2 catalyst.…”

Carbonylative Addition of Arylboronic Acids to Terminal Alkynes: A New Catalytic Access to α,β‐Unsaturated Ketones

“…[14] This reaction is one of the rare examples of a nucleophilic acylating reagent catalytically generated from carbon monoxide. [15] As continuation of this work, we thus anticipated that this reactivity could be enlarged to alkynes. We now report that arylboronic acids react with terminal alkynes under carbon monoxide pressure to yield selectively a,b-unsaturated ketones if appropriate condi-tions are used [Scheme 1, Eq.…”

“…The protonation thus occurs at the b-position of the enone and several proton donors may be involved in this final step. [15] The arylboronic acid itself or the water generated via the dehydration of arylboronic acid in the cyclic trimer anhydride can act as good proton donors. Another possibility arises from the protic nature of methanol which would favour this last step; this would be consistent with the fact that other solvents induce lower yields in 3aa.…”

New Synthesis of Furans: the Rhodium‐Catalysed Carbonylative Addition of Arylboronic Acids to Propargylic Alcohols/ Cyclisation Sequence

“…Later, transmetallation of the organic moiety of an organozinc reactant from zinc to a palladium centre followed by a carbonylation step also allowed the generation of an acylation reagent which could be reacted with a,b-unsaturated ketones. [7] In our laboratory, we used the transmetallation of the aryl group from the boron of an organoboron reagent to a rhodium centre to form the metal-carbon bond. Under CO, such an intermediate is carbonylated and affords rhodiumaroyl intermediates that could be reacted with vinyl ketones to synthesise 1,4-diketones (Scheme 1).…”