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

Abstract

The rhodium-catalysed carbonylative addition of arylboronic acids to propargylic alcohols yields gamma-hydroxy enones that are readily cyclised through a dehydration step to the corresponding furan analogues. The transformation was improved thanks to the screening of the reaction conditions and consequent improvements were obtained from the use of dicarbonylrhodium iodide [Rh(CO) 2 I] 2 as catalyst precursor. The generalisation of the reaction was then further investigated by employing variously substituted arylboronic acids and propargylic alcohols.

Supramolecular Alternating Block Copolymers via Metal Coordination

“…Propargylic alcohols are readily available by a variety of methods and constitute important key intermediates for the preparation of complex structures found in molecules of biological interest. Their reactivity with transition‐metal complexes of Rh4 and Ru5 for dehydrative transformations has been described in great detail in the literature. More recently, several methods in which gold catalysts are used for activation of this functional group towards nucleophilic attack either at the alkyne carbon or at the propargyl alcohol carbon have been developed.…”

Addition of Arylboronic Acids to Arylpropargyl Alcohols en Route to Indenes and Quinolines

“…Carbometalation of easily accessible propargylic alcohols provides a good access point to substituted allylic alcohols. , Various metals can promote arylation and alkylation of internal alkynes, but most protocols require the use of highly reactive and sensitive organometallic reagents . Rhodium-catalyzed arylation of alkynes with boronic acids bypasses this obstacle. , Since the report of this reaction by Hayashi and our work on unsymmetrical alkynes, , some applications of this chemistry have been reported; however unprotected propargylic alcohols are not well studied .…”

Gold(i)-catalyzed synthesis of furans and pyrroles via alkyne hydration

“…3 Amongst synthons leading to heterocyclic compounds, alkynes have appeared as particularly versatile substrates with various examples where these are transformed with the help of transition metals such as copper, 4 titanium, 5 ruthenium 6 and rhodium. 7 In the course of the last 10 years or so, gold complexes have emerged as powerful catalytic tools enabling numerous synthetic transformations. 8 As part of our ongoing programme focusing on the use of gold(I)-catalyzed reactions, we have recently developed a new precatalyst, [Au(IPr)OH] (IPr = 1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene), 9 which has efficiently been employed to generate the ubiquitous [Au(IPr)] + catalytically active species by the simple protonolysis using a Brønsted acid.…”