A catalyticenantioselectivesynthesis of dihydrofurans has been developed. 1,3-Dicarbonyl derivatives react with (E)-β,β-bromonitrostyrenes in the presence of a chiral bifunctional thiourea catalyst providing mild and efficient access to diverse polysubstituted dihydrofurans in good yields and enantioselectivities.
Diastereodivergent Synthesis of 3‐Spirocyclopropyl‐2‐oxindoles through Direct Enantioselective Cyclopropanation of Oxindoles
作者:Xiaowei Dou、Yixin Lu
DOI:10.1002/chem.201200655
日期:2012.7.2
reaction of oxindole was developed, in which oxindoles were employed as a dinucleophilic C1 synthon and bromonitroolefins with a dielectrophilic center were used as a C2 synthon (see scheme). An amino acid based multifunctional catalyst promoted the [2+1] reaction, giving the products in high yields and excellent enantioselectivities. A divergent synthesis of different stereoisomers of 3‐spirocyclopropyl‐2‐oxindoles
An aqueous isothiazolone formulation useful for antiseptic or antifungal treatment of various synthetic polymeric emulsions, which comprises (a) a specific isothiazolone compound, (b) water or an aqueous solvent and (c) a specific nitrobromo or cyanobromo compound.