Dess-Martin periodinane, and

Acyl nitroso compounds (3, Scheme 7.2) contain a nitroso group (-N=0) directly attached to a carbonyl carbon. Oxidation of an N-acyl hydroxylamine derivative provides the most direct method for the preparation of acyl C-nitroso compounds [10]. Treatment of hydroxamic acids, N-hydroxy carbamates or N-hydroxyureas with sodium periodate or tetra-alkyl ammonium periodate salts results in the formation of the corresponding acyl nitroso species (Scheme 7.2) [11-14]. Other oxidants including the Dess-Martin periodinane and both ruthenium (II) and iridium (I) based species efficiently convert N-acyl hydroxylamines to the corresponding acyl nitroso compounds [15-18]. The Swern oxidation also provides a useful alternative procedure for the oxidative preparation of acyl nitroso species [19]. Horseradish peroxidase (HRP) catalyzed oxidation of N-hydroxyurea with hydrogen peroxide forms an acyl nitroso species, which can be trapped with 1, 3-cyclohexanone, giving evidence of the formation of these species with enzymatic oxidants [20]. 

Acetylation of the hydroxy group and hydrolysis of the acetoxy group oxidation of the hydroxy group by Mn02 in ether or alternatively by Dess-Martin periodinane, and the reduction of the obtained aldehyde by NaBH4. 

The treatment of 1,4-, 1,5- and 1,6-diols with Dess-Martin periodinane, very often, leads uneventfully to dicarbonyl compounds74 or to hydroxycarbonyl compounds75 that are occasionally isolated as lactols.76 Sometimes, when a lactol is primarily obtained, it suffers a further oxidation to a lactone32,77 or it is transformed into an acetylated lactol.78 It has been proved that for the acetylation of lactols, both Dess-Martin periodinane and acetic acid generated during the oxidation must be present. The addition of pyridine does not avoid this reaction. 

IBX is able to transform tosylhydrazones and oximes into carbonyl compounds under very mild conditions.99 It is possible to selectively oxidize alcohols with IBX in the presence of sulfides.83,100 In fact, IBX has a lesser tendency to oxidize sulfides than Dess-Martin periodinane and in some sulfur-containing substrates it can be the oxidant of choice.36... 

Treatment of 9 with 3-lithiofuran (3-bromofuran, nBuLi) affords a 1 1 mixture of diastereomeric carbinols, which are readily separated by silica gel chromatography. However, the undesired C-2 -epimer of 28 is efficiently converted to the other diastereomer by oxidation of the alcohol with Dess-Martin periodinane and subsequent stereoselective oxazaborolidine-catalyzed reduction to give the desired 2 -(/ )-carbinol exclusively. This recycling of the undesired 2 -(S)-epimer allows for the transformation of 9 to 28 in 95 % yield overall. 

In the second step the alcohol is transformed to an aldehyde by means of the Swem oxidation. Other reagents to oxidize alcohols to aldehydes are e. g. Dess-Martin-periodinane and chromium reagents like PCC or PDC. 

The remaining and chiral four-carbon building block (5 )-F was prepared from ethyl (S)-3-hydroxybutanoate by protection with TBS chloride, reduction with diisobutylaluminum hydride, and oxidation with PCC. Aldol reaction of E and (S )-F furnished G. The aldol G was oxidized with Dess-Martin periodinane, and the resulting diketone H was treated with acid to give I. Deprotection of I gave (S)-141, which was levorotatory. The absolute configuration of the naturally occurring (-)-neuchromenin was thus determined as S. 

Compound 636 was converted to 638 under Mitsunohu conditions. Reduction upon heating led to the cyclization product 639. Coupling with a (R)-phenylalanine derivative yielded tetrapeptide 640, which was deprotected to give free diol 641. Diacid 642 was obtained after two consecutive oxidation steps with Dess-Martin periodinane and NaC102. Fmoc-deprotection, DCC-mediated cyclization (—> 643) and benzyl deprotection furnished diketopiperazine enf-WIN 64821 (644). 

Petrosin alkaloids (Scheme 11) were isolated from the sponge Petrosia se-riata, which was collected near Papua, New Guinea, in the 1980s [67-69]. In the racemic synthesis of petrosin, Heathcock et al. synthesized dimeric diazamacro cycle (110) by lactamization of 111 [70]. The oxidation of two hydroxyl groups of 110 with Dess-Martin periodinane and the removal of Boc groups led to double Mannich cychzation to give petrosins as a mixture of diastereoisomers. The desired petrosin (6) was isolated from the mixture in 23% yield by crystalhzation. 

A one-step preparation of acyl azides from aldehydes using Dess-Martin periodinane and sodium azide is known. The acyl azides 315 can be isolated without Curtius rearrangement due to the mild reactions conditions. Aliphatic and aromatic aldehydes can be... 

However, with the use of Lewis acids, a loss of stereochemical information was encountered when diastereomerically pure cyclopropyl derivative was converted to the respective spiroketal. With Dess-Martin periodinane and (in most cases also with IBX) without adding any additional reagent, the stereochemical information at the spirocenter is almost conserved that is, hydroxymethyl groups being below the plane of the six-membered ring are converted to the thermodynamically favored a-anomer, whereas a hydroxymethyl being above the plane of the ring led to the less thermodynamically favored p-anomer. 

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