High-pressure hydrogenated carbon deuterium

These data have been confirmed further by the results of the investigation of the hydroformylation of 3-(methyl-d3)-l-butene-4-d3 (I) under a high carbon monoxide partial pressure (125 atm) (11) (Scheme 1). 4-(Methyl-d3)pentanal-5-d3 (II) and 2-methyl-3-(methyl-d3)butanal-4-cf3 (III) were obtained in the proportion of 92% and 3.7%, respectively, with almost 100% retention of deuterium in the original position of the chain. 3-(Methyl-(23)pentanal-2-d2,3-(2i (IV) was 4.3% with practically 100% substitution of the hydrogen with deuterium on the tertiary carbon atom of the starting olefin (Scheme 1). These data are consistent with both Casey s and with our data for olefins with quaternary carbon atoms. 

The hydroformylation of several olefins in the presence of Co2(CO)8 under high carbon monoxide pressure is reported. (S)-5-Methylheptanal (75%) and (S)-3-ethylhexanal (4.8%) were products from (- -)(S)-4-methyl-2-hexene with optical yields of 94 and 72%, respectively. The main products from ( -)(8)-2,2,5-trimethyl-3-heptene were (S)-3-ethyl-6,6-di-methylheptanal (56.6%) and (R)-4,7,7-trimethyloctanal (41.2%) obtained with optical yields of 74 and 62%, respectively. (R)(S)-3-Ethyl-6,6-dimethylheptanal (3.5% ) and (R)(S)-4,7,7-trimethyloctanal (93.5%) were formed from (R)(S)-3,6,6-trimethyl-l-heptene. (+/S)-l-Phenyl-3-methyl-1-pentene, under oxo conditions, was almost completely hydrogenated to (- -)(S)-l-phenyl-3-methylpentane with 100% optical yield. 3-(Methyl-d3)-l-butene-4-d3 gave 4-(methyl-d3)pentarwl-5-d3 (92%), 2-methyl-3-(methyl-d3)-butanal-4-d3 (3.7%), 3-(methyl-d3)pentanal-2-d2,3-d1 (4.3%) with practically 100% retention of deuterium. The reaction mechanism is discussed on the basis of these results. 

The absence of free isomerized olefins, the Constance of isomeric composition of the products throughout the whole reaction in hydro-formylation experiments of 1-pentene and 4-methyl-1-pentene under high carbon monoxide pressure, the distribution of deuterium in the hydro-formylation products of 3-methyl-l-hexene-3-di and 3-(methyl-d3)-l-butene-4-d3, and the results of carbonylation of olefins containing a quaternary carbon atom indicate initial formation of an olefin-cobaltcarbonyl complex. Isomerization of this complex, resulting in 1,2 hydrogen shifts in its organic moiety, can produce the necessary precursors of the various aldehydes that are formed. 

---