Lactones, from diols

Hydroxylactones from cyanoacetals Diols from lactones... 

Diols from lactones via hydroxycarboxylic acids s. 11, 113 Alcohols from carboxylic acid esters GOOR GH2OH... 

Nakata showed that stoich. RuOyCCl oxidised steroidal diols to the corresponding ketones [237] electrogenerated RuO from RuO /aq. NaCl/Na(H3PO ) pH 4/ Pt electrodes converted diols to lactones and keto acids (Tables 2.1-2.4) [267] and RuCyaq. 10(0H)3/CC1 -CH3CN oxidised 3-(benzyloxy)-l,2-octanediol to the acid (Tables 3.4, 3.5) [107]. A diol was converted to a lactone by stoicheio-metric oxidation with RuOyCCl as part of the total synthesis of the quassinoid ( )-amarolide [82],... 

Typical examples are listed in Table 2.1. A few oxidations are effected by RuO but in general it is too powerful an oxidant for this purpose. The system RuCyaq. NaCl-CCy Pt anode oxidised benzyl alcohol to benzaldehyde and benzoic acid and p-anisaldehyde to p-anisic acid [24], and a wide range of primary alcohols and aldehydes were converted to carboxylic acids, secondary alcohols to ketones, l, -diols to lactones and keto acids from RuOj/aq. NaCl pH 4/Na(H3PO )/Pt electrodes (Tables 2.1-2.4). The system [RuO ] "/aq. K3(S303)/Adogen /CH3Cl3 oxidised benzyhc alcohols to aldehydes [30]. The oxidation catalyst TPAP (( Pr N)[RuO ]) (cf. 1.3.4) is extremely useful as an oxidant of primary alcohols to aldehydes and secondary alcohols to ketones without... 

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]. 

Diacids (succinic acid, adipic acid, suberic acid, and sebacic acid), diols (cyclohexane-1,4-dimethanol, 1,8-octanediol, 1,6-hexanediol and 1,4-butane-diol), and lactone (co-pentadecalactone) were purchased from Aldrich Chemical Co. in the highest available purity and used as received m-Caprolactone, a gift from Union Carbide, was dried over calcium hydride and distilled under reduced pressure in a nitrogen atmosphere. Humicola insolens cutinase was a gift from Novozymes (Bagsvaerd, Denmark). Lewatit OC VOC 1600 was received as a gift from Rohm and Haas. 

Selective Oxidations. The selective oxidation of 1,4 and 1,5 primary-secondary diols to lactones is a valuable application of this reagent. Few general mild reagents for the chemoselec-tive oxidation to the hydroxy aldehyde are available. The most widely known reagents are Pt and O2, and Dihydridotetrakis-(triphenylphosphine)ruthenium(II) Hydroxy aldehydes, in their lactol form, are then oxidized further to lactones. The use of TPAP is advantageous in that it is commercially available, employs mild catalytic reaction conditions, and reacts with high selectivity in unsymmetrical cases (eq 8). Lactones have also heen formed from primary-tertiary diols. ... 

The routes leading from lactone A have the advantage of a chiral source of starting materials. With the two chiral centers at C24 and C25 set, the problem reduces down to elaborating the B ring with the appropriate substituents. An early solution was provided in an unusual cyclization of the B ring via an intramolecular Michael addition to the unsaturated aldehyde formed from a nitrile oxide 1,3-dipolar cycloaddition to the allyl methyl ketal of lactone A [76]. This clever use of relative stereocontrol provided by the highly constrained and predictable transition states of both key reactions unfortunately resulted in a low yield. A more conventional approach conceptualized the addition of a sulfoxide [77] to 2 to yield a masked diol-ketone precursor which cyclizes under acidic catalysis. Elimination of the sulfoxide permitted the introduction of the hydroxy substituent at C19 of the spiroketal. 

Oxone in conjunction with OSO4 cleaves alkenes to ketones or carboxylic acids (eq 43). This protocol has the advantage over traditional methods in that there is no need for intermediate 1,2-diols. This method has been exploited in the direct synthesis of lactones from alkenols (eq 44) and tetrahydrofuran-diols from 1,4-dienes as well. ... 

The reaction can be applied to the synthesis of lactone from l,primary-primary diols bearing bulky substituents are oxidized at the sterically hindered position, although the chemoselectivity is modest (Scheme 18). It is noteworthy that the regioselectivity of the Ru-catalyzed reaction of unsymmehical primary-primary diols to lactones is opposite to the Pd-catalyzed reaction. ... 

We have developed a direct synthetic method for the one-pot synthesis of lactones, spirolactones, di-spirolactones, tertiary alcohols, and even 1,2-diols from the corresponding conjugated diene-magnesium reagents mediated by Rieke magnesium [122], The overall lactonization procedure can be considered... 

Lacfols via lactones, and diols from dicarboxylic acid anhydrides Labeled terpenoids... 

Related to the water elimination from cyclohexa-l,4-diols, one can cite the intramolecular nucleophilic displacement of the 4-hydroxycylohexl-yl tosylate derived from diol 109 into 7-oxanorbomane 110 (Scheme 14) and the synthesis of rac-famesiferol C that uses an intramolecular displacement of a cyclohexa-1,4-diol-derived lactone (conversion of 45 into oxanorbomane 46, Scheme 6). 

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