Assessment of butene-1,4-diols as starting materials for the preparation of π-Allyltricarbonyliron complexes

Synthesis of thieno[2,3-b]quinoxalines and pyrrolo[1,2-a]quinoxalines from 2-haloquinoxalines

“…However attempted application of the (basic) ring-closing conditions again led to complex mixtures-clearly the choice of an ester for protection was not well advised. 2,6-Dichloroquinoxaline 3 1c was coupled with propargyl alcohol tetrahydropyranyl ether 4 giving 2c and this was reacted with bromine. We were surprised to find that the two stereoisomeric products each contained three bromine atoms-two had added as usual to the triple bond but a third had been incorporated elsewhere.…”

“…To a degassed solution of 2,6-dichloroquinoxaline (1.5 g, 7.5 mmol) and 3-(tetrahydropyran-2-yloxy)prop-1-yne 4 (1.1 g, 8.25 mmol) in acetonitrile (40 ml) and triethylamine (7.5 ml), palladium() acetate (130 mg, 0.57 mmol), copper() iodide (182 mg, 0.95 mmol), and triphenylphosphine (200 mg, 0.76 mmol) were added, under nitrogen. The mixture was heated at 60 ЊC for 4 h. After evaporation of the organic solvents, the residue was diluted with water and extracted with dichloromethane.…”

Reactions of chelated η3-pentadienyl iron complexes with nucleophiles

“…Rigid normal and medium-sized metallacycles with p-ligands are particularly suited for studying the delicate balance between these two factors in bond forming processes. (g 3 -allyl) ferralactones such as 1 can be readily obtained from reactions of diironnonacarbonyl with either vinyl epoxides [1][2][3][4][5], but-2-ene-1,4-diols [6] or the cyclic sulfites of but-3-ene-1,2-diols [7]. They have been exploited in regioselective reactions involving the allyl ligand, eventually leading to prominent target structures such as blactones and -lactams, 1,3-dienes and dihydropyranones [8,9].…”

Pd-Catalyzed Allylic Substitution with Enantiomerically Pure Catalysts and Chiral Non-Racemic Substrates: A New Approach to Catalyst-Based Regiocontrol, Preliminary Communication

“…With the catalyst derived from ligand (S)-6a, the same regioisomer (S)-Scheme 5 8 predominates as with an achiral (triphenylphosphine)palladium complex. However, the regioselectivity induced by the chiral catalyst is higher (97 : 3 vs. 86 : 14). Obviously, the catalyst-induced regioselectivity and the substitution pattern in the allyl system both favor nucleophilic attack adjacent to the Ph group (matched case).…”

“…The required optically active substrate 16 was prepared from the corresponding racemic propargyl alcohol by oxidation with MnO 2 and enantioselective reduction of the ketone with (R)-Alpine-Borane [13], followed by reduction of the triple bond with Red-Al [14] and acetylation. The absolute configuration of (S)-16 was assigned by oxidative degradation of the corresponding allyl alcohol to methyl (À)-(R)-2-methoxy-2-phenylacetate (see above).…”