Ketones, saturated, carbon monoxide elimination

R = H or Me) (59,62). It is interesting that this reaction proceeds readily in solution since reactions in which carbon monoxide is eliminated from a saturated ketone usually occur in the vapor phase. 

Saturated ketones undergo a large number of photochemical reactions which include photoreduction, elimination of a-heterosubstituents, a-cleavage, 7-hydrogen transfer, and elimination of carbon monoxide. In this chapter only photochemical rearrangements of saturated ketones will be considered. 

Palladium-catalyzed ketone synthesis B. The reaction mixture is saturated with carbon monoxide, which intervenes in step 2 by forming a palladium(II) carbonyl complex. Before the transmetalation (above referred to as step 3) takes place a rearrangement is interposed. The ligand Rmisa rji cd undergoes a [l,2]-shift from Pd(II) to the carbon atom of carbon monoxide, leading to the formation of an acylpalladium(II) complex with the structure P lllsa llra cd-(C=0)-Pd(-X) L j. With regard to the above-mentioned steps 3-4 it behaves like the acyl-Pd(II) complex of the ketone synthesis A and, after reductive elimination, i.e. in step 5, yields... 

The elimination of carbon monoxide from cyclic ketones is a fairly common process. The reaction occurs photochemically with saturated systems the mechanism of this process was discussed in Part A, Section 11.3. Facile thermal expulsion occurs only in molecules having special structural features. The elimination of carbon monoxide from bicyclo[2.2.1]heptadien-7-ones can occur by a concerted mechanism. In fact, generation of bicyclo[2.2.1]heptadien-7-ones is usually accompanied by... 

The role of palladium in organic synthesis continues to be explored and exploited. Enol stannanes are monoalkylated by allylic acetates in the presence of tetrakis(triphenylphosphine)palladium, Enol stannanes give higher selectivity for monoalkylation than enolate ions or silyl enol ethers. High regioselec-tivity is observed for alkylation at the less substituted end of the allyl moiety. Olefins, after complexation to palladium(ll), alkylate enolate anions. The organopalladium product may be converted into saturated ketones, or into enones by /3-elimination, or acylated with carbon monoxide (Scheme... 

---

See also in sourсe #XX -- [ ]

---