Vanadium‐Catalyzed Asymmetric Epoxidation of Allylic Alcohols Mediated by (+)‐Norcamphor‐Derived Hydroperoxide

Abstract

A protocol for the asymmetric epoxidation of allylic alcohols has been established that employs VO(acac)2 as catalyst, the commercial achiral hydroxamic acid, N‐hydroxy‐N‐phenylbenzamide, and optically pure (+)‐norcamphor‐derived hydroperoxide as oxygen atom donor and chiral source. Variation of the reaction parameters has a significant effect on the level of asymmetric induction. Under optimized conditions, the epoxy alcohols have been isolated in good yields with up to 67 % ee and complete control of the diastereoselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Oxidovanadium(IV) Complexes of 3-Hydroxy-4-pyrone and 3-Hydroxy-4-pyridinone Ligands: A New Generation of Homogeneous Catalysts for the Epoxidation of Geraniol

“…Finally, when compared to other oxidovanadium/ hydroxamic acid catalytic systems reported in literature [19,21,[23][24][25][26][29][30][31], these two families of pyrone and pyridinone oxidovanadium(IV) complexes lead to similar or higher 2,3-epoxygeraniol regioselectivity and yield in a shorter reaction time. Furthermore, they provide several advantages to the catalytic reactions, including the possibility of using low catalyst loadings, mild reaction conditions (at room temperature over a shorter reaction time), aqueous oxidants and easy work-up procedures.…”

“…The asymmetric induction has also been achieved through the combination of optically active hydroperoxide oxidants with Electronic supplementary material The online version of this article (doi:10.1007/s10562-010-0281-8) contains supplementary material, which is available to authorized users. achiral hydroxamic acid ligands [31,32]. In this context, the quest for efficient and selective oxidovanadium catalysts for epoxidations still continues to be a thriving topic in Fine Chemistry.…”

“…Due to the importance of such reactions, several research groups have been engaged in the design of novel and efficient vanadium catalysts for the stereoselective epoxidation of allylic and homoallylic alcohols. A major breakthrough in this area has been the synthesis of several active and enantioselective vanadium complexes with chiral and nonchiral hydroxamic acid ligands containing diverse structural features [10,11,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Sharpless and co-workers were the first researchers to report a promising chiral vanadium catalyst for this reaction involving [VO(acac) 2 ] and a chiral hydroxamic acid, with t-BuOOH as oxidant [17,18].…”

Recent advances in vanadium catalyzed oxygen transfer reactions

“…More recently, Lattanzi and coworkers described the use of the chiral hydroperoxide derived from (S)-norcamphor 41 (Scheme 6) in reactions catalyzed by both VO(acac) 2 and VO(O-i-Pr) 3 using N-hydroxy-N-Scheme 6. Vanadium catalyzed epoxidation of allylic alcohols using chiral hydroperoxides 39 and 41 [45,47,48].…”

“…phenylbenzamide 42 as ligand [48]. Stereoselectivities up to 61% were achieved with epoxide 36b using 10% of catalyst and 15% of ligand (Scheme 6).…”