198136-53-7Relevant academic research and scientific papers
The reactions of dicarbonylbis(phosphorus donor) iron fragments with tertiary propargyl alcohols
Gauss, Christine,Veghini, Dario,Orama, Olli,Berke, Heinz
, p. 19 - 38 (2007/10/03)
The reaction of the mixture of Fe(CO)2(PEt3)2N2 (1a) and [Fe(CO)2(PEt3)2]2N2 (1b) with propargyl alcohols HC ≡ C-CR1R2OH (R1=R2=Me; R1=Me, R2=Et; R1=Me, R2=iPr; R1=Me; R2=tBu; R1=R2=tBu; R1=R2=Ph) in THF affords isolable Fe(CO)2(PEt3)2(H)(C≡C-CR1R2OH) complexes (R1=R2=Me 2a; R1=Me, R2=Et 2b; R1=Me, R2=iPr 2c; R1=Me, R2=tBu 2d; R1=R2=tBu 2e; R1=R2=Ph 2f). Complexes 2a-d underwent dehydration in hexane in the presence of silylated silica to yield vinylvinylidene complexes Fe(CO)2(PEt3)2=C=C(H)R′C-CR″R? (R′=Me, R″, R?=H 3a; R′=R″=Me, R?=H 3b; R′=R?=Me, R″=H 3c; R′=R″=R?=Me 3d; R′=tBu, R″=R?=H 3e). 2e and 2f did not eliminate water. However, double deprotonation with n-BuLi and deoxygenation with acetyl chloride ultimately produced then their formal products of dehydration: di(t-butyl) or diphenylallenylidene(dicarbonyl)bis(triethylphosphine)iron compounds 4a or 4b. The reactions of dicarbonylbis(trimethylphosphite)iodoferrate 1b with the same propargyl alcohol derivatives HC=C-CR1R2OH as mentioned above resulted in the formation of dicarbonylbistrimethylphosphite(vinylidene)iron derivatives Fe(CO)2[P(OMe)3]2=C=C(H)CR1R2OH (R1=R2=Me) 7a; R1=Me; R2=Et 7b; R1=Me, R2=iPr; 7c; R1=Me, R2=tBu 7d; R1=R2=tBu 7e; R1=R2=Ph 7f). Dehydration processes of 7a-f in the presence of Al2O3 or SiO2 led to allenylidene or vinylvinylidene complexes Fe(CO)2[P(OMe)3]2 =C=C=CR1R2 (R1=Me, R2=tBu 8a; R1R2=tBu 8b; R1=R2=Ph 8c) or Fe(CO)2[P(OMe)3]2=C=C(H)CR′=CR″R? (R′=Me, R″=R?=H 9a; R′=Et, R″=R?=H 9b; R′=R″=Me, R?=H 9c; R′=R?=Me, R″=H 9d; R′=iPr, R″=R?=H 9e; R′=R″=R?=Me 9f; R′=tBu, R″=R?=H 9g). 8c was also prepared by an alternative route starting from 1c and HC≡C-CPh2OAc which provided a higher yield. 7e and 8b were characterized by single crystal X-ray diffraction studies.
