Propargylic alcohols dicarbonylation

Cycloaddition between Propargylic Alcohols and Cyclic 1,3-Dicarbonyl Compounds... 

The thiolate-bridged diruthenium complex 101 can promote a cycloaddition reaction between propargylic alcohols and 1,3-dicarbonyl compounds to provide 3-acyM//-pyrans in excellent yield (Scheme 33). The reaction proceeds via formation and alkylation of the allenylidene complex 102 to form the vinylidene intermediate 103, which upon cyclization furnishes 4//-pyrans (Scheme 33) <2004JOC3408>. 

A ruthenium-catalyzed three-component reaction between propargylic alcohols, 1,3-dicarbonyl compounds, and primary amines leading to fully substituted pyrroles was developed <07CEJ9973>. Cyclohexa[a]pyrroles ( azabicyclo[4.3.0] systems ) were formed by a three-component sequence involving allenic ketones, primary amines, and acryloyl chloride <07SL431>. An oxidative dimerization sequence involving arylpyruvates in the presence of ammonia was the key step in an approach to the pyrrole natural product, lukianol A <07S608>. 

Tetrasubstituted furans were obtained by a simple and efficient protocol starting from propargylic alcohols and 1,3-dicarbonyl compounds in the presence of a ruthenium-catalyst and CF3CO2H <07ASC382>. 

A metal-catalyzed tandem 1,4-addition/cyclization of propargyl alcohols with Michael acceptors such as alkylidene-malonates has been developed. In the presence of catalytic amounts of zinc triflate and triethylamine, various 2-alkylidene-l,3-dicarbonyl compounds react with propargyl alcohols to give 3- or 4-methylenetetrahydrofurans in excellent yields (Equation 96) <20040L2015>. 

Formation of these products can be understood by assuming that the carbonylation of propargyl alcohol under high pressure involves two different reaction pathways. One is the Pd(0)-catalyzed carbonylation and the other is the Pd(II)-catalyzed oxidative carbonylation 2,3-Butadienoate (80) is a primary product of the Pd(0)-catalyzed carbonylation, but further attack by carbon monoxide at the central sp carbon of 80 under high carbon monoxide pressure yields itaconate (81) as the dicarbonylation product. Formation of aconitate (83) is explained by the oxidative dicarbonylation of a triple bond with Pd(II) species, followed by Pd(0)-catalyzed allylic carbonylation. As a supporting evidence, methyl aconitate (83) was... 

Propargylic compounds undergo facile palladium-catalyzed mono- and dicarbonylations, depending on the reaction conditions [9]. The carbonylation of propargylic alcohols has... 

P-Lactones. Vicinal cfj-dicarbonylation of tertiary propargyl alcohols is observed in the presence of Pdlj and KI under CO. 

More recently, Nebra and Gimeno applied this concept to the synthesis of pentasubstituted 3-acylpyrroles 369 from 1,3-dicarbonyl compounds 368 [318]. The efHdency and the scope of this transformation were significantly improved by the use of the Ru(II) catalyst in the presence of trifluoroacetic acid co-promoter. The reaction tolerates 1,3-diketones, (J-ketoesters, various secondary propargylic alcohols 195... 

For the acid-induced cydization of 96 to the furans 97, an allenic intermediate 98 seems to be reasonable. In a comparable Cu(OTf)2-promoted cyclocondensation, secondary propargyl alcohols and 1,3-dicarbonyl compounds afford tetrasubstituted furans [32]. 

An analogous propargylation/amination/cycloisomerization sequence with pyrrole formation was established for propargylic alcohols 92, 1,3-dicarbonyl compounds and primary amines with catalysis of In(III) chloride [128]. 

Scheme 57 Ru-catalyzed [3+3] cycloaddition between propargylic alcohols and cyclic 1,3-dicarbonyl compounds to 4,6,7,8-tetrahydrochromen-5-ones and with 2-naphthols to IH-naphtho[2,1-bjpyrans...

Thiolate-bridged dirutheniutn complexes catalyze the [3-f3] cycloaddition reaction between propargylic alcohols and cyclic 1,3-dicarbonyl compounds to afford 4,6,7,8-tetrahydrochromen-5-ones or 4//-cyclopenta[b]pyran-5-ones [193] and with 2-naphthols or phenols to afford l//-naphtho[2,l-b]pyrans and 4//-l-benzo-pyrans, respectively [194]. This cycloaddition is considered to proceed by stepwise propargylation and intramolecular cyclization (carbon and oxygen nucleophile additions) reactions, where ruthenium allenylidene and vinylidene complexes are the key intermediates (Scheme 57). Enantioselective mthenium-catalyzed [3-f3] cycloaddition of propargylic alcohols with 2-naphthols has also been described [195]. 

W. Huang, J. Wang, Q. Shen, X. Zhou, Yb(OTf)3-catalyzed propargylation and allenylation of 1,3-dicarbonyl derivatives with propargylic alcohols one-pot synthesis of multi-substituted furocoumarin, Tetrahedron 63 (2007) 11636-11643. 

V. Cadierno, J. Gimeno, N. Nebra, Anovel propargylation/cycloisomerization tandem process catalyzed by a ruthenium(U)/trifluoroacetic acid system one-pot entry to fully substituted furans from readily available secondary propargylic alcohols and 1,3-dicarbonyl compounds,... 

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