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Stereochemistry of Back-Biting Processes Stereoselectivity

Tsuruta observed in the cyclooligomerization of t-butyloxirane that both (R)- and (S)-t-birtyloxiranes predominantly yield cyclic tetramers however, all the other macrocycles (from dimer to octamer) have also been observed in smaller concentrations  [Pg.119]

This stereoselectivity in cyclooligomerization has not been observed for (RS)-t-butyloxirane. The presence of two enanthiomers, (R) and (S), apparently decreases the probability of the formation of the preferred conformation of the linear chain which leads to the G G T sequence. [Pg.120]

Highly specific oligomerization was also observed for trans- and cis-1,2-dimethyl-thiirane. [Pg.120]

Trans-l,2-dimethylthiirane gives a cyclic product, 1,2,5-trithiepane, which is formed in a kinetically distinct back-biting step when monomer is already converted into a linear polymer  [Pg.120]

The trans monomer has the configuration (SS or RR). In the Sn2 attack in the propagation step, inversion of configuration on the carbon atom being attacked [Pg.120]


See other pages where Stereochemistry of Back-Biting Processes Stereoselectivity is mentioned: [Pg.119]   


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