Chiral compounds sulfoxides

Chiral acetylenic sulfoxides and related compounds in synthesis of heterocycles 97MI39. 

Sulfoximines are an example of a tetracoordinated chiral compound, and their optical isomers have been isolated. Their stereochemistry was also studied approximately 30 years ago.43 Endocyclic sulfoximines are an example of chiral heteroaromatics. Endocyclic sulfoximines 26 were optically resolved on a chiral column for the first time by Allenmark and co-workers in 1995.44 The stereoisomers were obtained by amination and subsequent cyclodehydration of optically active o-carboxyphenyl sulfoxide with hydrazoic acid or 0-(me-sitylenesulfonyl) hydroxylamine (Scheme 14). 

This chapter covers only the chiral compounds that are cited in the literature by virtue of their optical activity. To keep the chapter to an acceptable length, a discussion of the stereochemical properties of sulfenamides showing axial chirality is omitted (17). Similarly, to limit the scope of the review, the chemistry of penicillin, cephalosporin sulfoxides and related compounds (14,18,19), steroidal sulfoxides (15,16), and other naturally occurring chiral sulfur compounds (4) is not discussed. For the same reason, only selected results are discussed and in some cases only references are given to recent papers and review articles on special topics. 

A stereogenic center may be located at carbon, as in numerous ordinary chiral compounds and in spiranes12, or at other elements such as sulfur13-14 (see the chiral sulfoxides pp 401 and 411), phosphorus15-17, nitrogen18, silicon19-20, or a metal21. 

Chiral compounds (Continued) epoxy alcohols, 141 formulas, xiii xvii hydroxystannanes, 318 liquid crystals, 350 molecular lattics, 347 natural, 1 NMR spectra, 282 olefins, 173 oxetanones, 326 phenols, 287 see also Binaphthol phenylbutenes, 172 protonating agents, 324 sulfoxides, 159 sulfur ylides, 328 synthesis, I... 

Another application of additions to chiral vinylic sulfoxides constitutes the Hantzsch-type reaction of methyl 3-aminocrotonate with compound (109), yielding the dihydropyridine derivative (110) as a single... 

S-chiral compounds were synthesized through lipase-catalyzed reactions. For example, chiral sulfoxide was synthesized through lipase-catalyzed hydrolysis of the ester to give (R)-ester and (.V)-acid (Figure 18).19... 

Chiral Acetylenic Sulfoxides and Related Compounds in Organic Synthesis... 

Chiral vinyl sulfoxides can also be prepared Horner-Emmons reaction of carbonyl compounds with a-phosphoryl sulfoxides which are obtained from lithiated dimethyl methylphosphonate and (-)-menthyl (S)-p-toluenesulfinate (eq 8). However, this reaction applied to carbonyl compounds often gives a mixture of the (E) and (Z) isomers of the vinylic sulfoxide. 

Chiral vinyl sulfoxides have been coupled to aryl iodides to give a chiral allylic aryl compounds (C=C-CH2—Ar), in a three-step procedure with good enantio-selectivity. ... 

Reports on the ability of microorganisms to selectively oxidize various types of sulfides to the corresponding chiral sulfoxides have grown significantly in the last few years (33). Chiral sulfoxides are evident in a variety of pharmaceutical and agricultural chemical compounds (33). The w hydroxylase from Pseudomonas oleovorans has been shown to produce a variety of chiral aliphatic sulfoxides from corresponding sulfides (34). Vinyl sulfox-... 

The bulk of oxidations with tert-butyl hydroperoxide consists of epoxidations of alkenes in the presence of transition metals [147, 215, 216, 217, 218]. In this way, a,p-unsaturated aldehydes [219] and ketones [220] are selectively oxidized to epoxides without the involvement of the carbonyl function. Other applications of tert-butyl hydroperoxide such as the oxidation of lactams to imides [225], of tertiary amines to amine oxides [226, 227], of phosphites to phosphates [228], and of sulfides to sulfoxides [224] are rare. In the presence of a chiral compound, enantioselective epoxidations of alcohols are successfully accomplished with moderate to high enantiomeric excesses [221, 222, 223]. 

The last two molecules are more straightforward. The tricyclic compound has a plane of i= -.etry vertically down the middle and is not chiral. The sulfoxide is a simple example of a K2 .Tgenic atom other than carhon. Sulfoxides are tetrahedral with the oxygen atom and the lone . i-Dove and below the plane as drawn. This one is chiral. 

Molecular Kohn-Sham Potentials. 180 107-168 Lee AWM, Chan WH (1997) Chiral Acetylenic Sulfoxides and Related Compounds in Organic... 

The application of chiral sulfoxides to the asymmetric synthesis of biologically active compounds has recently been reviewed [3]. Conjugate addition to chiral vinyl sulfoxides has been used by several research groups to achieve the enantioselective synthesis of natural products. For example, intramolecular asymmetric conjugate addition of a nitrogen nucleophile to a chiral vinyl sulfoxide (Scheme 3) was studied by Pyne and applied to the enantioselective synthesis of (-R)-carnegine and other alkaloid systems (Scheme 3) [10]. 

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