Carboxidation linear alkenes

Carboxidation of linear alkenes is presented in Table 7.8 [173]. The location of the C=C bond and configuration of intermediate oxadiazoline complex are two important parameters with these substrates. For terminal alkenes, the complex may have configuration I and II (Figure 7.4). Complex I has the oxygen bound to the first carbon atom, and its decomposition leads to an aldehyde. Complex II has the oxygen bound to the second carbon atom, and its decomposition leads to a ketone. However, decomposition of the latter complex may occur also in a different way, involving... 

In conclusion, we can say that the liquid-phase carboxidation of alkanes can be applied to various substrates, induding linear, cyclic, heterocydic alkenes and their derivatives, yielding the corresponding ketones and aldehydes with selectivities in many cases of >90%. 

Similar to internal alkenes, carboxidation of the rubber involves intermediate formation of an oxadiazoline cycle (Figure 7.7). Decomposition of the cycle without cleavage of the C=C bond (route 1) is accompanied by the formation of a ketone and does not lead to change in the molecular weight. Decomposition with cleavage (route 2) leads to fragmentation of the macromolecule with the formation of two smaller fragments a linear aldehyde R2-CH2-CHO and a carbene R -CH2-CH , which further isomerizes into the terminal alkene Rj-CH=CH2. 

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