Rhodium-Catalyzed Carbonylation of Spiropentanes

Abstract

Spiropentanes undergo carbonylation under an atmosphere of carbon monoxide in the presence of a rhodium(I)−phosphine catalyst, giving 3-methylcyclopent-2-enones. The catalytic cycle involves two mechanistically different carbon−carbon cleavage processes. The spiropentane carbonylation was successfully applied to a short synthesis of (±)-β-cuparenone.

Pauson–Khand reaction of fluorinated compounds

“…The synthetic potential of this methodology was demonstrated by the formal total synthesis of α-cuparenone [74,75], a bicyclic sesquiterpene that belongs to the cuparene family isolated from Thuja orientalis [76]. More specifically, the authors designed a simple route to enone 67, a key intermediate in several previous Contrary to the results observed with norbonadiene and ethylene, which both furnished a single regioisomer, the use of norbornene afforded mixtures of regioisomers, although the same α-CF 3 isomer was favored in all cases.…”

“…The synthetic potential of this methodology was demonstrated by the formal total synthesis of α-cuparenone [ 74 – 75 ], a bicyclic sesquiterpene that belongs to the cuparene family isolated from Thuja orientalis [ 76 ]. More specifically, the authors designed a simple route to enone 67 , a key intermediate in several previous total syntheses [ 77 – 78 ].…”

Cu‐ and Ni‐Catalyzed Conjugated Additions of Organozincs and Organoaluminums to α,β‐Unsaturated Carbonyl Compounds

“…Recently, the Ni-catalyzed conjugated addition of Me 2 Zn has been also applied in a new synthesis of (±)-β-cuparenone [162]. A nice example of the Ni-catalyzed conjugated addition of a diarylzinc to a sterically hindered enone was demonstrated by Sakai et al [163].…”

Rhodium‐catalyzed restructuring of carbon frameworks

“…Given in Scheme is an illustrative example, which embeds in a single catalytic cycle both of the two elementary steps of carbon–carbon bond cleavage 2. Spiropentane is a hydrocarbon molecule lacking any heteroatom functionalities and its main carbon framework consists of only sp 3 carbons.…”