1.5- DioIs

Tietze, L. F., Geissier, H., Gewert, J. A., Jakobi, U. Tandem-bisaikyiation of 2-triaikyisiiyi-1,3-dithiane a new sequentiai transformation for the synthesis of C2-symmetricai enantiopure 1,5-diois and p,P -dihydroxyketones as weii as of enantiopure 1,3,5-triois. Syn/eff 1994, 511-512. 

With reagent IIS, however, the corresponding allylboronate intermediate 116 is thought to favor transition structure 117 in which die a-substituent is in a pseudo-axial orientation to escape steric interactions with the bulky tetraphenyl dioxaborolane (Equation 57). This way, a Z-configured allylic alcohol unit of opposite stereochemistry is obtained in product 118. Such steric control had been demonstrated before by the work of Hoffman and co-workers on a-chiral aUylboronates (Section 6.3.1.3). The usefulness of this powerful tandem aUylation/allylation strategy was demonstrated with several examples of both types of 1,5-dioIs, 114 and 118. 

Conjugated dienes are often converted into 2,3-unsaturated 1,4-dioIs by successive treatment with peracids and hydroxides (R.B. Woodward, 1957). 

CH2Br2, NaOH, CH2CI2, cetylN Me3Br , heat, 81% yield. This method is effective for both cis- and fra/z5-l,2-dioIs. 

Reaction of the 17-keto compound (54) with potassium acetylide in liquid ammonia gives the 17a-ethynylandrost-5-ene-3) ,I7)5-dioI (55). ° Similar results have been obtained with A-ring aromatic 17-ketones. ... 

Favorskii rearrangement, 159, 176 Formation of hetero-radicals, 238 2-Formyl-A-nor-5a-androstan-l 7 -oI, 415 2-Formyl-A-nor-5 a-androst-1 -en-17 S-ol, 416 6/3-Formyl-B-nor-5 -cholestane-3, 5 -dioI 3-acetate, 432... 

Two hundred milligrams of the diacetate of (dl)-reg.-1-phenyl-2-dichloroacetamidopropane-1,3-dioi is added to a mixture consisting of 0.25 cc of concentrated nitric acid and 0.25 cc of concentrated sulfuric acid at 0°C. The reaction mixture is stirred until solution is complete, poured onto 25 g of ice and the mixture extracted with ethyl acetate. The ethyl acetate extracts are evaporated under reduced pressure and the diacetate of (dl)-reg.-l-p-nitrophenyl-2-dichloroacetamidopropane-1,3-diol so produced purified by recrystallization from ethanol MP 134°C. 

A mixture of 22 grams of Oi-(p-chlorophenoxy)isobutyric acid, 3.8 grams of 1,3-propane-dioi, 0.5 gram of p-toiuenesulfonic acid and 150 ml of xylene was refluxed. When the theoretically calculated amount of water had been removed, the xylene solution was washed with dilute aqueous sodium bicarbonate and then the xylene was distilled off. The residue was distilled under reduced pressure to give 11 grams (47% yield) of 1,3-propanediol bis[a-(p-chlorophenoxy)isobutyrate] boiling at 197° to 200°C/0.03 mm Hg. 

C 5H2j02 846-46-8) see Androstanolone Estrone (3p,17p) -androst-5-ene-3,17-diol 3-acetate (C21H32O3 1639-43-6) see Mesterolone Testosterone (3p,17p)-androst-5-ene-3,17-dioI 3-acetate 17-benzoate... 

Reaction of perthiophosphonic anhydrides (64) with amines leads first to (105) and then, by further attack, to (106). With ammonia itself the second addition proceeds at the same phosphorus atom as the initial attack, giving (107) and (108). The anhydride (64) is also reported to react with 1,3-dioIs to give cyclic phosphonyl disulphides (109). Thermal decomposition of phenylphosphinic anhydride (110) may lead to the formation of PhP since in the presence of benzil the formation of the phosphorane (111) was observed. ... 

Diethoxytriphenylphosphorane, (C6H5),P(OC2H5)2 (1). The phosphorane is obtained by reaction of diethyl peroxide (caution) with triphenylphosphine at 0-70°. Cyclodehydration of dioIs to ethers. 1,3-, 1,4-, and 1,5-Diols react with 1 to... 

Figure 1.7 Some other statins containing a 1,3-syn-dioi side chain.

In connection with our own work on the enzyme-catalysed hydrolysis of cyclohexene epoxide with various fungi we made the unexpected observation that the microorganism Corynesporia casssiicola DSM 62475 was able to interconvert the (1R,2R) and (1S,2S) enantiomers of the product, trans cyclohexan-1,2-dioI 25. As the reaction proceeded the (1R,2R) enantiomer was converted to the (1S,2S) enantiomer [20]. If the racemic trans diol 25 was incubated with the growing fungus over 5 days, optically pure (> 99 % e. e.) (1 S,2S) diol 25 could be isolated in 85% yield. Similarly biotransformation of cis (meso) cycIohexan-1,2-diol 26 yielded the (1S,2S) diol 25 in 41 % (unoptimized) yield (Scheme 11). 

Dioxasilacyclopentanes are readily hydrolyzed in neutral media at RT to HO—C— C—0SiR20H with bulky substituents at the silicon atom (R = Bu ) an alkaline medium (pH 10) is required <82TL487l>. In MeOH with K2CO31,2-dioIs are obtained in 75-90% yield at RT <92TL2099>. Organo Li and Mg compounds react very rapidly at low and ambient temperatures with these cyclic disiloxanes (Equation (5)) <88CR(307)1351>. 

Condensation of 1,3-Diois and Congeners with Carbonyl Groups... 

At low temperatures in inert solvents (such as methylene dichloride) a controlled polymerization can be effected using various acids and alkylating agents. These initiators include boron trifluoride etherate, triethylaluminum, trityl hexachloroantimonate, triethylam-monium hexachloroantimonate, diethyloxonium hexafluoroantimonate, p-toluenesulfonic acid and diethylzinc or cadmium-1,2-dioI complexes. Crystalline, high molecular weight... 

To a flask containing 11.6 gm (0.10 mole) of traws-cyclohexane-1,2-dioI and 18.6 gm (0.24 mole) of pyridine in 200 ml of methylene chloride is added drop-wise, over a 2 hr period at 0°C, 23 gm (0.19 mole) of thionyl chloride dissolved in 50 ml of methylene chloride. The pyridine hydrochloride is filtered and the methylene chloride solution is successively washed with 0.01 N hydrochloric... 

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