Bifurandione. I. Preparation and Characterization

Rhodium-Catalyzed Carbonylative Synthesis of Heterocycles

“…of methanol was added, the reaction proceeding smoothly and completely. Rhodium complexes such as [Rh(CO) 2 Cl] 2 and RhCl 3 showed almost the same activity as Rh 6 (CO) 16 under the same reaction conditions. Moreover, study of the substrates indicated that primary alcohols gave higher yields of the corresponding indanone derivatives than secondary alcohols, possibly because of the acidity of the alcohols.…”

“…Another example of carbonylation of alkene-alkyne using aldehyde as CO source and in the presence of Rh(dppp) 2 Cl catalyst was reported by Shibata and co-workers in 2002 (Scheme 24) [44]. Among a variety of aldehydes, cinnamaldehyde showed the best efficiency as the CO source.…”

“…To examine the ring-expansion process, cis-1-isopropyl-3-methyl-2-phenylaziridine was subjected to benzene with [Rh(CO) 2 ]Cl 2 as the catalyst and the corresponding cis-3,4-disubstituted β-lactams was isolated in 81% yield, indicating that the carbonylation had taken placed with retention of the stereochemistry of the substituent groups (Scheme 5). Moreover, the remarkable regio-, stereo-, and enantiospecificity of the β-lactam synthesis suggested that it might be a promising route to synthesize corresponding asymmetric compounds from racemic aziridines in the presence of an appropriate chiral ligand.…”

“…In 2002, Brummond and co-workers found that when alkynyl allenes were treated with [Rh(CO) 2 Cl] 2 and processed via [2+2+1] cycloaddition reaction, a variety of 4-alkylidene cyclopentenones can be produced without α-alkylidenecyclopentenones (Scheme 25). The scope and limitations of the rhodium-catalyzed allenic Pauson-Khand-type reaction were examined in detail.…”

“…In this work, different carbonyl complexes and solvents were examined in detail, and it was found that the [Rh(CO) 2 Scheme 24 Rhodium-catalyzed carbonylation of alkene-alkyne using aldehyde as CO source [55], based on previous work on the rhodium-catalyzed carbonylation of isoxazolidines with regioselective insertion of CO into the N-O bond affording tetrahydro-1,3-oxazin-2-ones [56]. When N-benzylisothiazolidine is reacted with 5 mol% of (1,5-cyclooctadiene)rhodium(I) dimer in benzene in the presence of 1,000 psi of carbon monoxide at 130 C for 24 h, a 58% yield of 2H-1,3-thiazin-2-one can be achieved, and the addition of 5 mol% of potassium iodide can increase the yield to 70% (Scheme 28).…”