Ester sulfinic

Note 2. A large number of experimental examples are given in Ref. 108. In some cases methyl sulfonates can be successfully applied when the use of the sulfinic esters leads to mixtures of 1,1- and 1,3-substitution products. [Pg.169]

The utility of methanesulfinyl chloride lies in its great chemical reactivity. Through its ready hydrolysis, it serves as a convenient source of methanesulfinic acid. It reacts at low temperature with aromatic amines to form sulfinamides, and with alcohols to form sulfinate esters. When it is hydrolyzed in the presence of an equimolar quantity of sulfenyl chloride, a thiol-sulfonate ester is produced. [Pg.65]

Sulfinic esters, aromatic, by oxidation of disulfides in alcohols, 46, 64 Sulfonation ot d,l camphor to d,l-10-camphorsulfomc acid, 45,12 Sulfoxides, table of examples of preparation from sulfides with sodium metapenodate, 46,79 Sulfur dioxide, reaction with styrene phosphorus pentachlonde to give styrylphosphomc diclilonde, 46,... [Pg.138]

Aryl- and alkyl-magnesium halides were the first reagents used to form sulfoxides from sulfinate ester 19 and related (— )-menthyl arenesulfinates (equations 564,665,758 and 866). Whereas optically pure esters produced the homochiral sulfoxides shown in equations (5), (6) and (7), the ester shown in equation (8) was an oily mixture of four diastereomers which led to formation of a meso sulfoxide and a d, l pair enriched in one enantiomer. A homochiral sulfoxide was obtained by fractional crystallization. [Pg.64]

Allenyl and 1- and 2-alkynyl sulfoxides have also been prepared by reaction of organomagnesium halides with sulfinate ester 19. 1-Alkynyl p-tolyl sulfoxides were prepared in good yield from 1-alkynylmagnesium halides plus ester 19 in toluene (equation ll)63. The corresponding organolithium compound was unsatisfactory as a... [Pg.66]

Schneider and Simon82 prepared / -ketosulfoxides 47a and 47b by sulfinylation of the dianions of the methyl acetoacetates 48a and 48b with sulfinate ester 19 followed by decarboxylation of the intermediate products (Scheme 2). Apparently this avoids racemiz-ation experienced by others in the direct synthesis of these compounds9. /J-Ketosulfoxides are also available from the reaction of the anion derived from methyl p-tolyl sulfoxide with esters (see Section II.E). They can also be obtained, in some cases, through the hydrolysis of a-sulfinylhydrazones whose synthesis is described below. Mention has already been made of the synthesis of 2-p-tolylsulfinylcycloalkanones such as 32. [Pg.67]

Esters and amides may be sulfinylated. Addition of a mixture of t-butyl acetate and sulfinate ester 19 to a THF-ether solution of magnesium diisopropylamide led to the formation of (R)-(+)-f-butyl p-toluenesulfinylacetate (49) in 90% yield (equation 14)7. t-Butyl propanoate and butanoate also underwent this sulfinylation to give 50 and 51 in yields of 68 and 45%, respectively83. The diastereomeric ratio was 1 1 for 50 and 3 7 for 51. These esters may also be obtained by alkylation of 49. Similarly, treatment of a-lithio-A, A -dimethylacetamide with sulfinate ester 19 gave (R)-( + )-N, Ar-dimethyl-p-toluene-sulfinylacetamide (52) (equation 15)84. [Pg.67]

Enolates derived from various imino compounds have been sulfinylated in reactions analogous to those shown by equations (14) and (15). Some representative examples are shown in equations 16-18. Here again, these compounds have been utilized in asymmetric syntheses. Addition of sulfinate ester 19 to a THF suspension of a-lithio-N,N-dimethylhydrazones, derived from readily available hydrazones of aldehydes and ketones, leads to a-sulfinylhydrazones in good yield, e.g. 53 and 54 (equations 16 and 17)85,86. Compounds 53 and 54 were obtained in a 95/5 and 75/25 E/Z ratio, respectively. The epimer ratio of compound 53 was 55/45. Five other examples were reported with various E/Z and epimeric ratios. [Pg.68]

The lithium enolate of ethyl V-methoxyacetimidate (55) was also successfully sulfmy-lated by treatment with sulfinate ester 19 (equation 19)87. Sulfoxide 56 was used in an asymmetric synthesis of some /1-hydroxy esters. [Pg.69]

J-Enamino and /i-imino sulfoxides are formed by the reaction of lithioenamines with sulfinate ester 1990. In the six examples reported, enamines were formed exclusively in three cases (equation 20), a mixture of enamines and imines in two cases, and an imine exclusively in one case (equation 21). [Pg.69]

Various sulfur compounds have been sulfinylated by treatment of the appropriate carbanion with sulfinate ester 19. Compounds 5992,6093,6194 and 6295 were prepared in this way, /i-disulfoxides (63) have also been prepared, as shown earlier by equation (8). [Pg.69]

An a-phosphoryl sulfoxide (4) has also been prepared by the reaction of the appropriate carbanion with sulfinate ester 19 (see also Section II.A.l)18. Ugi and coworkers prepared (S, R, S)-65 by reaction of (R, R)-64 with ester 19. The (S, S, R) diastereomer was prepared from (S, S)-6496. [Pg.70]

In view of the successful preparation of so many homochiral sulfoxides via the reaction of nucleophilic species with sulfinate ester 19, it appears likely that the reaction is capable of extension to provide still more examples of potentially useful sulfoxides. [Pg.70]

Although carbanionic and enolate species are most often sulfinylated using sulfinate esters, particularly homochiral ester 19, other tricoordinate S(IV) compounds may be used in their place. Sulfinamides (66) and cyclic sulfite ester-amides (67) are two examples of such compounds. [Pg.70]

The other fragmentation pathways are typical for diaryl sulfoxides1-4-6,1. A corresponding ortho effect was found in chlorodiphenyl ethers and sulfides but not in sulfones12 (12) were the sulfinate ester rearrangements1-4,6,11 and the consequent formation of the m/z 125 and m/z 159 ions suppress the other possible fragmentations of the molecular ions (equation 4). It is also noteworthy that the ratio [m/z 125] [m/z 159] increases with increasing distance between the chlorine and the sulfur (equation 4). [Pg.129]

Phenanthro[4,5-b, c, d]thiophene 4-oxide (19) and 4,4-dioxide (20)15 undergo first the well-known sulfenate (22) or sulfinate ester (23) rearrangements1 4,6, respectively (equation 6). The sulfoxide loses an oxygen atom and enters the fragmentation pathway of 18 or loses HCO (more likely in two steps) from 22. Both sulfenate and sulfinate ions can fragment further via 21 after losing a sulfur atom or eliminating SO5, respectively. [Pg.130]

Sharpless and Klunder22 are developing a new procedure for conversion of sulfonyl chlorides directly into menthyl sulflnate esters using trimethyl phosphite as a reducing agent (equation 2). This method, starting with sulfonyl chlorides rather than with the much less available sulfinyl chlorides, should allow access to an even wider range of sulfinate esters and, ultimately, to various chiral, non-racemic sulfoxides. [Pg.825]

Also, sulfinyl chlorides (precursors to sulfinate esters) have recently been prepared directly from disulfides (equation 3)23. [Pg.825]

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