Hydroalumination locoselectivity

Finally, the high locoselectivity or chemoselectivity of hydroalumination toward substrates having both C==C and C C bonds is exemplified by the reaction of diisobutylaluminum hydride with 1-octen-7-yne (7). The only organoaluminum product detected (8) was that of a regioselective syn stereospecific addition to the bond (equation 3). 

The main locoselective features of hydroalumination, which are discussed in some detail in Section 3.11.2.3 are (i) (DsC bonds are attacked in preference to (D=C bonds (ii) terminal HC C and H2C=CH groups are hydroaluminated much more rapidly than internal C C and CH=CH linkages and (iii) electron-releasing substituents on the carbon-carbon unsaturated group increase the rate of hydroalumination (Table 4). Illustrative are the relative initial rates for PhC 3isCE with E = Ph, Me, H,... 

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