Carbon-Heteroelement Bond-Forming Reactions

Cerium isopropoxide catalyzes the highly diastereoselective pinacol coupling of aliphatic and aromatic aldehydes (eq. (15)) [139]. 

S Carbon-Heteroelement Bond-Forming Reactions 3.2.5.5.1 Hydrogenation and Related Processes 

The following catalytic olefin transformations are another domain of metallocene complexes [140], and hence are closely related to those described in the preceding sections, e. g., with respect to type of catalyst and mechanistic steps. 

Type 4 and 5 alkyl complexes also catalyze the regioselective hydrogenation of acyclic imines (190 psi of H2, 90 °C, TOF = 0.40 h ) [147]. The stoichiometric reaction of A -benzylidene(trimethylsilyl)imine with 4(Sm CH(SiMc3)2) yielded a desilylated Cp 2Sm-imine-amido complex with a four-membered Sm(NSi-Me3)(CPh)N=CHPh chelate ring which converts further to Se-symmetric 

Although terminal alkynes are metallated by 4(Sm Me)/THF, internal alkynes do undergo effective hydrosilylation [156]. 

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