Stereoselective and stereospecific

This process is both stereoselective and stereospecific. When applicable, a trans di-substituted alkene will be favored over a cis disubsti-tuted alkene. 

According to a widely accepted cyclopolymerization mechanism,67,75 there are two distinct stereochemical events for these cyclopolymerizations the already discussed stereoselectivity and stereospecificity of olefin insertion, which determine the tacticity of the polymer, and the stereoselectivity of the cyclization step, which determines the cis or trans configuration of the rings. 

Molecular mechanics analyses of the kind described in previous sections are able to rationalize not only the stereoselectivity (and stereospecificity) of regioregular primary insertion steps but also the stereoselectivities relative to occasional secondary monomer insertions as well as relative to primary insertions following these secondary insertions.37d... 

The terms stereoselective and stereospecific properly refer only to reactions in which diastereomerically different materials may be formed or destroyed during the course of the reaction. Stereoselective reactions are all those in which one diastereomer (or one enantiomeric pair of diastereomers) is formed or destroyed... 

Stereoselective and stereospecific addition of the zinc carbenoid Solutnn... 

Finally, microbiological hydroxylation has been shown to be highly stereoselective and stereospecific using adamantyl substrates 369. ... 

Fig. 15.14. Evidence for stereoselectivity and stereospecificity with regard to the butadiene moiety in a pair of Diels-Alder reactions. The cis,trans-l,4-disubstituted 1,3-butadiene forms cyclohexene with a trans arrangement of the methyl groups. The trans,trans-1,4-disubstituted 1,3-butadiene forms cyclohexene with ris-methyl groups.

Fig. 16.10. Nickel-catalyzed alkenylation of Grignard compounds occurrence of stereoselectivity and stereospecificity.

Fig. 16.31. Stereoselective and stereospecific Pd(0)-cata-lyzed alkenylations of copper acetylides with iodoalkenes at the beginning of a two-step...

Fig. 16.36. Stereoselectivity and stereospecificity of Heck coupling reactions with isomeric iodoalkenes.

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