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
Formal Total Synthesis of Brevisamide by Using a Tandem Isomerization/C-O and C-C Bond Formation Reaction
作者:Shivalal Banoth、Saurabh Maity、Sudheer R. Kumar、J. S. Yadav、Debendra K. Mohapatra
DOI:10.1002/ejoc.201600142
日期:2016.5
stereoselective formaltotalsynthesis of brevisamide is described that proceeds through a convergent pathway and utilizes our own tandem isomerization/C–O and C–C bond formation reaction as the key step to construct the trans-2,6-disubstituted dihydropyran ring system. Other significant reactions in this synthesis include an iodolactonization, a Crimmins-modified “non-Evans” syn aldol reaction, and a Ho