Reactivity of (1-methoxycarbonylpentadienyl)iron(1+) cations with hydride, methyl, and nitrogen nucleophiles

Abstract

The reaction of tricarbonyl and (dicarbonyl)triphenylphosphine (1-methoxycarbonyl-pentadientyl)iron(1+) cations 7 and 8 with methyl lithium, NaBH3CN, or potassium phthalimide affords (pentenediyl)iron complexes 9a-c and 11a-b, while reaction with dimethylcuprate, gave (E,Z-diene)iron complexes 10 and 12. Oxidatively induced-reductive elimination of 9a-c gave vinylcyclopropanecarboxylates 17a-c. The optically active vinylcyclopropane (+)-17a, prepared from (1S)-7, undergoes olefin cross-metathesis with excess (+)-18 to yield (+)-19, a C9-C16 synthon for the antifungal agent ambruticin. Alternatively reaction of 7 with methanesulfonamide or trimethylsilylazide gave (E,E-diene)iron complexes 14d and e. Huisgen [3+2] cyclization of the (azidodienyl)iron complex 14e with alkynes afforded triazoles 25a-e.

Molybdenum Trihydride Complexes: Computational Model of Oxidatively Induced Reductive Elimination of Dihydrogen

“…Unfortunately, the precursor of this oxidatively induced reductive elimination (OIRE) reaction, [Cp*Mo­(dppe)­H 3 ] + , was only characterized in situ by electron paramagnetic resonance (EPR) spectroscopy . To increase the stability of this precursor, Poli and co-workers synthesized and characterized two, more sterically crowded and protected, molybdenum trihydride complexes, [(1,2,4-C 5 H 2 t Bu 3 )­Mo­(PMe 3 ) 2 H 3 ] (Cp t Bu MoH 3 ) and [(C 5 H i Pr 4 )­Mo­(PMe 3 ) 2 H 3 ] (Cp i Pr MoH 3 ), which also undergo H 2 elimination through the OIRE mechanism. , The OIRE mechanism has been observed not only for hydrogen release reactions but also as an important step in the reaction mechanism for numerous transition-metal complexes. − …”