Stereochemistry of the reaction of Si–phenyl silenes with butadienes: elaboration of the silacycloadducts to provide a novel route to substituted lactones
作者:Mahesh J. Sanganee、Patrick G. Steel、Daniel K. Whelligan
DOI:10.1039/b404175e
日期:——
silacycles accompanied by variable amounts of competing ene, [2 + 2] and silene dimer by-products. The silacycles are formed with good chemo- and stereo-selectivity and provide access to diols and lactones via a phenyl-triggered Fleming-Tamao oxidation.
Exploiting the vicinal disubstituent effect on the diastereoselective synthesis of γ and δ lactones
作者:Elisabetta Brenna、Francesco Dalla Santa、Francesco G. Gatti、Giuseppe Gatti、Davide Tessaro
DOI:10.1039/c8ob02715c
日期:——
diastereoisomer ring closes substantially more rapidly than the syn isomer ring; (ii) the anti-vic effect is much stronger than the classical Thorpe–Ingold effect (known also as the gem-disubstituent effect), instead the syn diastereoisomers have rate constants comparable to that of the gem-disubstituted ester; (iii) the vic-effect can be enhanced by increasing the steric hindrance of one of the two substituents