Propargylsilanes as Reagents for Synergistic Gold(I)‐Catalyzed Propargylation of Carbonyl Compounds: Isolation and Characterization of σ‐Gold(I) Allenyl Intermediates

Abstract

Reported herein is the isolation and characterization, for the first time,o fas-gold allenyl complex as an intermediate in gold catalysis.T his intermediate was captured during the study of anovel gold(I)-catalyzed propargylation of carbonyl compounds with propargylsilanes.Notably,the goldcatalyzedp ropargylation reaction, which proceeds with aldehydes and ketones,c an be driven to the formation of either homopropargyl silyl ethers or the in situ synthesis of corresponding 2-silyl-4,5-dihydrofurans.

Main Avenues in Gold Coordination Chemistry

“…Recently, this has been corroborated and gold allenyl species have been isolated and characterized as intermediates in the study of a gold catalyzed propargylation reaction (Scheme 49). 179 Hashmi and co-workers prepared a dinuclear NHC gold(I) allenyl complex, [Ph(IPrAu) C=C=CH(AuIPr)] (76) by reaction of 1-phenylpropyne, as the allene source, with nBuLi and further addition of [AuCl(IPr)] at −40 °C. The compound decomposes during column chromatography but could be characterized by NMR spectroscopy (Scheme 50).…”

Regioselective Silylations of Propargyl and Allyl Pivalates through Ca-Promoted Reductive C(sp3)–O Bond Cleavage

“…Propargylsilanes are vital intermediates in organic synthesis, with intensive investigations into transformations and synthetic tactics reported in the past few decades. While propargylsilanes are not readily available, they can be prepared by transforming propargylsilane derivatives or under harsh reaction conditions in multiple steps using highly flammable tert -butyllithium or toxic copper­(I) cyanide. ,− In 2019, Chen and co-workers reported an efficient method for delivering propargylsilanes from vinylidenecyclopropanes; however, the starting materials for this process are not straightforward, and the use of complicated reagents and multi-step reactions, including functional group protection and deprotection, are required.…”

Efficient method for propargylation of aldehydes promoted by allenylboron compounds under microwave irradiation

“…Although there are several stereoselective methods described for the reaction of propargyl or allenyl organometallics with carbonyl compounds [8][9][10][11][12][13][14], the control of the regioselectivity is still a major concern. This is mainly due to the metallotropic rearrangement of propargyl and allenyl organometallics in solution resulting in mixtures of the two reagents [15].…”