Phenylthio ester

For (n = 3) (CF3C02)2lPh, H2O, CH3CN or MeOH, 1-10 min, 85-100% yield.A phenylthio ester is stable to these conditions, but amides are not. 

CF,C02)2lPh, H2O, CH3CN, 85-99% yield. In the presence of ethylene glycol the dithiane can be converted to a dioxolane (91% yield) or in the presence of methanol to the dimethyl acetal. The reaction conditions are not compatible with primary amides. Thioesters are not affected. A phenylthio ester is stable to these conditions, but amides are not. The hypervalent iodine derivative l-(t-butylperoxy)-l,2-benziodoxol-3(l/f)-one similarly cleaves thioketals."... 

Treatment of the phenylthio ester with Pd/C and TESH results in reduction to the aldehyde. ... 

Phenyl and phenylthio esters have proven to be advantageous in TiCl4-mediated additions, perhaps because they are slightly more acidic than the alkyl analogs. The reactions show syn diastereoselectivity, indicating that Z-enolates are formed.43... 

PhenyUhlo)nitromethane is a convenient reagent for the synthesis of derivatives of 3-methylfuranfor the preparation of a-substituted phenylthio esters via the homologation of aldehydes, and for the preparation of bicyclic... 

The Claisen ester enolate reaction has proved to be extremely useful in the synthesis of a large number of natural products.3 In addition, the rearrangement has been extended to allow the preparation of useful intermediates such as a-alkoxy esters,88 329 33 336 343 a-phenylthio esters,339344-345 a- and [3-amino acids,340 346-350 a-fluoro esters,351 cycloalkenes,352353 tetronic acids,354 and dihydro-pyrans.355-357... 

Essigsaure Amino- -O-phenylthio-ester (Hydrobromid) XV/1, 413F. Pyrrol 4-(Ethylthio-carbonyl)-2-formyl- E5, 851 f. (H - CO-SR) Thiohenzoesaure 4-Methoxy- -hydroxamid E5, 1285 (SR - NH-OH)... 

Radical cyclization is not limited to reaction with a C=C unit (see 15-29 and 15-30), and reactions with both C=N and C=0 moieties are known. Reaction of MeON=CH(CH2)3CHO with Bu3SnH and AIBN, for example, led to trans-2-(methoxyamino)cyclopentanol in good yield.Conjugated ketones add to aldehyde via the p-carbon under radical conditions (2 equivalents of Bu3SnH and 0.1 equivalent of CuCl) to give a p-hydroxy ketone.Addition of radical to the C=N unit of R C=N SPh ° or R—C=N—led to cyclic imines. Radical addition to simple imines leads to aminocycloalkenes. Radical also add to the carbonyl unit of phenylthio esters to give cyclic ketones. 

The di-Grignard method has also been applied to reactions of disubstituted amino [41,42], phenoxy, and phenylthio esters [42] to provide difunctional cycloalkanols examples include the conversion of esters 53 to cyclopentanols 54 [Eq. (20) 42]. Similarly, lactones can be converted to diols as in the formation of cyclopentanol 56 from lactone 55 [Eq. (21) 43]. 

Additive aldol reaction. An anri-selective synthesis of 5-phenylthio esters of 3-hydroxy-2-phenylthiomethylalkanethiolates from a mixture of acryloyl chloride, PhSLi and aldehydes is mediated by MgBr2 OEt2. 

It is also possible to reduce 2-methyl-3-oxo-2-phenylthio esters stereosclcctively to give preferentially the indicated products, the best reagent being calcium borohydride. In most cases the stereoselectivities are very satisfactory. The main motivation for this development was the conversion of the products to the corresponding (Z)-alkenes83. 

The chlorination of trimethylsilylmethyl sulfides with NCS and trifluoroacetic acid affords the product of chlorodesilation in high yield.3 The degradation of carboxylic acids to ketones can be achieved by a-sulfenation followed by reaction with NCS in the presence of NaHC03 (eq 6). The 5 -chlorosulfonium ion intermediate undergoes a decarboxylative Pummerer-like rearrangement to afford the ketone upon hydrolysis. a-Phenylthio esters... 

Under similar conditions a-phenylthio esters 9 afford fluorides 10 (Scheme 3.5) [25]. The mechanism of this Pummerer-type reaction involves initial nucleophilic addition of the sulfur atom to the electrophilic iodine center to form the iodosulfonium salt 11. The liberated fluoride anion acts as a base with resultant formation of the classical Pummerer intermediate 12. Subsequent trapping of cation 12 with fluoride anion yields the final product 10 (Scheme 3.5) [25]. 

Nitro- 1-phenylthioalkenes (1), on reaction with teri-butyl hydroperoxide, are converted into epoxides and these species react with nucleophiles (halide salts, horon trifluoride etherate, trifluo-roacetic acid, MsOH) to provide a-substituted phenylthio esters (eq 3). Alternatively, Michael addition of nucleophiles (aUcox-ides, Phth, Ts, malonate) to 1-nitro-l-phenylthioalkenes and ozonolysis of the intermediate nitronate gave similar adducts (eq 4), including a-amino and a-hydroxy acid derivatives. ... 

Conversion of Esters and a,/9-Unsaturated Esters into Phenylthio Esters. Esters are converted into phenylthio esters by heating with phenyl thioborate in refluxing xylene (140 °C) (eq 1), but the same transformation can be done at room temperature with phenyl thioaluminate. With the aluminum reagent, a, -unsaturated esters give products contaminated with the )S-(phenylthio) ester, but the boron reagent does not suffer from this disadvantage (eq 2). 

Methodology. Filippov has reported a one-pot procedure to prepare phosphate, phosphorothioate and phosphorofluoridate monoesters as well as pyrophosphate monoesters of nucleosides. This versatile approach made use of di(p-methoxybenzyl)-A, A -diisopropylphosphoramidite. While little information was provided on the preparation and stability of the phosphoramidite reagent, its use in the reaction with benzoate-protected thymidine in the presence of dicyanoimidazole as an activator yielded the di(p-methoxybenzyl)phosphite of thymidine [46]. This phosphite could subsequently be oxidised (Scheme 3) to the phenylthioate ester [47a], the phosphate monoesters [47b], the phosphoramidate [47c, d], the phosphorofluoridate [47e], the nitrophenolate diester [47f] and to the fully protected dinucleotide [47g]." ... 

Pummerer Reaction. The reagent transforms sulfoxides in the presence of catalytic amounts of zinc iodide into the corresponding a-silyloxy sulfides (eq 1). Vinyl sulfoxides undergo a Michael-Pummerer type reaction to give y-silyloxy-y-phenylthio esters (eq 2). ... 

---