Catalytic asymmetric dihydroxylation

Catalytic asymmetric dihydroxylation of alkenes with participation of insoluble polymer-bound cinchonine alkaloids 99SLI181. 

Scheme 8. The first catalytic asymmetric dihydroxylation (developed by Sharpless).

Bennani et al.26 also reported a short route to Mosher s acid precursors via catalytic asymmetric dihydroxylation (Scheme 1-7) ... 

The major breakthrough in the catalytic asymmetric dihydroxylation reactions of olefins was reported by Jacobsen et al.55 in 1988. Combining 9-acetoxy dihydroquinidine as the chiral auxiliary with /V-methylmorphine TV-oxide as the secondary oxidant in aqueous acetone produced optically active diols in excellent yields, along with efficient catalytic turnover. 

TABLE 4-10. Enantiomeric Excess of Diols Obtained by Catalytic Asymmetric Dihydroxylation of Alkenes61... 

Scheme 16. Catalytic asymmetric dihydroxylation used by Corey to prepare 109, used in his 1985 total synthesis of ovalicin, in the optically pure form (1994).

Along with catalytic asymmetric epoxidation, the related dihydroxylation of olefins is another venerable catalytic enantioselective process that is widely used by the modern organic chemist. An application of this important transformation may be found in Corey s 1994 preparation of optically pure 109 (Scheme 16), an intermediate in Corey s 1985 total synthesis of ovalicin.1181 The catalytic asymmetric dihydroxylation that affords 108 solves one of the most challenging problems in the total synthesis installment of the tertiary alcohol center with the appropriate relative and absolute stereochemistry. 

For a recent review on the catalytic asymmetric dihydroxylation, see Reference 518. 

SCHEME 178. Osmium-catalyzed catalytic asymmetric dihydroxylation of olefins by H2O2 as terminal oxidant... 

Alkyl- or 3-aryl-2,4-oxazolidinediones via photochemical cyclization, ° organonickel-mediated carbonylation, ° cyclization of A-alkenyl-a-acet-amides, ° carboxylation and cyclization of 2-propynamides, °" cyclization of (9-carbamates of a-hydroxy acetic acids and esters,cyclization of a-hydroxy acetamides,and catalytic asymmetric dihydroxylation (ADH) of A-alkenoyl-2-oxazolidinones. ... 

Phthalazines are commonly used as ligands in transition metal cataysis since the structure provides a planar backbone with coordinating nitrogens. One of the most prevalent phthalazine-based ligands is known as (DHQD)2PHAL (154) <94CR2483>. A recent example of the use of 154 was in the catalytic asymmetric dihydroxylation by osmium tetroxide with air as the ultimate oxidant reported by Krief and co-worker <99TL4189>. 

Success in the use of Ti tartrate catalyzed asymmetric epoxidation depends on the presence of the hydroxyl group of the allylic alcohol. The hydroxyl group enhances the rate of the reaction, thereby providing selective epoxidation of the allylic olefin in the presence of other olefins it also is essential for the achievement of asymmetric induction. The role played by the hydroxyl group in this reaction is described in a later section of this chapter. The need for a hydroxyl group necessarily limits the scope of this asymmetric epoxidation to a fraction of all olefins. Fortunately, allylic alcohols are easily introduced into synthetic intermediates and are very versatile in organic synthesis. The Ti tartrate catalyzed asymmetric epoxidation of allylic alcohols has been applied extensively as documented in the literature and in this review. The development of methods aimed at catalytic asymmetric epoxidation of unfunctionalized olefins is described in Chapter 6B, whereas the catalytic asymmetric dihydroxylation of olefins, which provides an alternate method for olefin functionalization, is described in Chapter 6D. 

The cis dihydroxylation of olefins mediated by osmium tetroxide represents an important general method for olefin functionalization [1,2]. For the purpose of introducing the subject of this chapter, it is useful to divide osmium tetroxide mediated cis dihydroxylations into four categories (1) the stoichiometric dihydroxylation of olefins, in which a stoichiometric equivalent of osmium tetroxide is used for an equivalent of olefin (2) the catalytic dihydroxylation of olefins, in which only a catalytic amount of osmium tetroxide is used relative to the amount of olefin in the reaction (3) the stoichiometric, asymmetric dihydroxylation of olefins, in which osmium tetroxide, an olefinic compound, and a chiral auxiliary are all used in equivalent or stoichiometric amounts and (4) the catalytic, asymmetric dihydroxylation of olefins. The last category is the focus of this chapter. Many features of the reaction are common to all four categories, and are outlined briefly in this introductory section. 

This brief outline of historical developments in osmium tetroxide-mediated olefin hydroxy-lation brings us to our main subject, catalytic asymmetric dihydroxylation. The transition from stoichiometric to catalytic asymmetric dihydroxylation was made in 1987 with the discovery by Sharpless and co-workers that the stoichiometric process became catalytic when N-methyl-... 

The focus of this chapter is to acquaint the reader with details of catalytic asymmetric dihydroxylation with osmium tetroxide and the scope of results that one can expect to achieve with current optimum conditions. The literature through mid-1992 has been reviewed in compiling this chapter. Osmium tetroxide catalyzed hydroxy]ations of olefins and acetylenes are the subject of an extensive review by Schroder published in 1980 [2a]. A comprehensive review of research and industrial applications of asymmetric dihydroxylations is in preparation [2b]. 

Catalytic asymmetric dihydroxylations (ADs) are easy reactions to perform. The reaction actually requires water and is insensitive to oxygen and so can be carried out without fear of exposure to the atmosphere. The reaction uses a multicomponent reagent system, which allows... 

CATALYTIC ASYMMETRIC DIHYDROXYLATION—DISCOVERY AND DEVELOPMENT 6D.2.6. Enantioselectivity Mnemonic... 

D.3. CATALYTIC ASYMMETRIC DIHYDROXYLATIONS BY OLEFIN SUBSTITUTION PATTERN... 

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