Nucleophilic Epoxidation of α‘-Hydroxy Vinyl Sulfoxides
摘要:
The nucleophilic epoxidation of a variety of alpha'-(1-hydroxyalkyl) vinyl sulfones and sulfoxides has been studied. The sulfones give rise to anti oxiranes with modest (E) or excellent (Z) selectivities and in good yields. The (E)-sulfoxides display low reactivity within a reinforcing/nonreinforcing scenario. The use of t-BuOOLi in Et2O allows for a highly syn-selective epoxidation-oxidation. The (Z)-sulfoxides display a remarkably high reactivity under these conditions. The reinforcing (S,Ss) diastereomers (3e-g) yield hydroxy sulfinyl oxiranes with high yields and selectivities. In contrast, the (R,Ss) diastereomers (4e-g) show diminished reactivities and a very substrate-dependent stereochemical outcome. The structure of these oxiranes has been secured by chemical correlations and an X-ray crystal structure.
Nucleophilic Epoxidation of α‘-Hydroxy Vinyl Sulfoxides
摘要:
The nucleophilic epoxidation of a variety of alpha'-(1-hydroxyalkyl) vinyl sulfones and sulfoxides has been studied. The sulfones give rise to anti oxiranes with modest (E) or excellent (Z) selectivities and in good yields. The (E)-sulfoxides display low reactivity within a reinforcing/nonreinforcing scenario. The use of t-BuOOLi in Et2O allows for a highly syn-selective epoxidation-oxidation. The (Z)-sulfoxides display a remarkably high reactivity under these conditions. The reinforcing (S,Ss) diastereomers (3e-g) yield hydroxy sulfinyl oxiranes with high yields and selectivities. In contrast, the (R,Ss) diastereomers (4e-g) show diminished reactivities and a very substrate-dependent stereochemical outcome. The structure of these oxiranes has been secured by chemical correlations and an X-ray crystal structure.
Asymmetric Claisen Rearrangements on Chiral Vinyl Sulfoxides
作者:Roberto Fernández de la Pradilla、Carlos Montero、Mariola Tortosa、Alma Viso
DOI:10.1002/chem.200801680
日期:2009.1.5
Highly diastereoselective Claisen rearrangements of acyclic allyl vinyl ethers bearing a chiralsulfoxide at C‐5 provide γ‐δ‐unsaturated aldehydes or ketones with up to two consecutive asymmetric centers in the molecule whilst preserving a useful vinyl sulfoxide. The reactivity of related vinyl sulfides and sulfones has also been examined in this work.
Nucleophilic Epoxidation of α‘-Hydroxy Vinyl Sulfoxides
作者:Roberto Fernández de la Pradilla、Jorge Fernández、Pilar Manzano、Paloma Méndez、Julián Priego、Mariola Tortosa、Alma Viso、Martín Martínez-Ripoll、Ana Rodríguez
DOI:10.1021/jo026182s
日期:2002.11.1
The nucleophilic epoxidation of a variety of alpha'-(1-hydroxyalkyl) vinyl sulfones and sulfoxides has been studied. The sulfones give rise to anti oxiranes with modest (E) or excellent (Z) selectivities and in good yields. The (E)-sulfoxides display low reactivity within a reinforcing/nonreinforcing scenario. The use of t-BuOOLi in Et2O allows for a highly syn-selective epoxidation-oxidation. The (Z)-sulfoxides display a remarkably high reactivity under these conditions. The reinforcing (S,Ss) diastereomers (3e-g) yield hydroxy sulfinyl oxiranes with high yields and selectivities. In contrast, the (R,Ss) diastereomers (4e-g) show diminished reactivities and a very substrate-dependent stereochemical outcome. The structure of these oxiranes has been secured by chemical correlations and an X-ray crystal structure.