1- Hexen hydrogen donor

The results for the cyclization of the l,l,5-trimethyl-5-hexen-l-yl radical, formed from the reaction of l,l,5-trimethyl-5-hexenyl-l-bromide (3) with Bu3SnH/AIBN, are shown in eq. 3.2. These results indicate that the ratio of 5-exo-trig marmer/6-endo-trig manner depends on both the temperature and concentration of Bu3SnH. Thus, as the concentration of Bu3SnH at 40 °C is decreased (which means the decrease of the concentration of the hydrogen donor), both a decrease of the direct reduction product,... 

Catalytic hydrogen transfer from a hydrogen donor molecule to an unsaturated substrate sometimes presents advantages over hydrogenation by molecular hydrogen. This type of reaction can be catalyzed by a number of ruthenium or rhodium catalysts. Cycloocta-1,5-diene and hexa-1,5-diene can be selectively reduced to cyclooctene and a mixture of hexenes, respectively, by Rh6(CO)16 via hydrogen transfer from isopropanol.The reaction proceeds at 145°C and a CO pressure of 45 bar. For cycloocta-1,5-diene... 

Sternberg et al. (28a) postulated that [HPe(CO)4] can exist as a dimer because (among other reasons) of its ability to function as a donor of molecular hydrogen. The ion was shown to be a catalyst for olefin isomerization shaking 1-hexene at room temperature with an ether solution of [HFe(CO)4] for 24 hours isomerized all the 1-hexene to 2-and 3-hexenes. Similar isomerizations also have been reported to be catalyzed by H2Fe(CO)4 (28b) and by Fe(CO)j (29). 

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