Useful Enantioselective Bicyclization Reactions Using an N-Protonated Chiral Oxazaborolidine as Catalyst
作者:Gang Zhou、Qi-Ying Hu、E. J. Corey
DOI:10.1021/ol035542a
日期:2003.10.1
[reaction: see text] Nine examples are reported of enantioselective [4 + 2] cycloaddition reactions of achiral, acyclic substrates to form chiral bicyclo[4.3.0]nonane or bicyclo[4.4.0]decane derivatives.
Intramolecular Diels–Alder reactions using chiral ruthenium Lewis acids and application in the total synthesis of ent-ledol
作者:Sirinporn Thamapipol、E. Peter Kündig
DOI:10.1039/c1ob06121f
日期:——
ligand BIPHOP-F and a Cp or an indenyl ‘roof’ can efficiently catalyze asymmetric intramolecular Diels–Alder reactions of trienes to form bicyclic adducts with good to excellent asymmetric induction. This reaction forms the key step in a totalsynthesis of ent-ledol in 96% ee. The synthesis also helps to clarify the stereochemical assignment of ledol and inconsistencies in the measured optical rotation
IntramolecularDiels-Alderreaction of 2-methyl-(E,E)-2,7,9-decatrienal catalyzed by chiral acyloxyborane complex proceeds with high stereo and enantioselectivities.