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2‘-Deoxyribofuranosylpurine derivatives bearing an N-tert-butylaminoxyl group (1a and 2a) were synthesized via oxidation of the corresponding N-tert-butylhydroxylamines (1b and 2b), which were synthesized by lithiation of 8-TIPS-6-chloropurine (3) at the 2-position and the following reaction with 2-methyl-2-nitrosopropane. Treatment of 1b and 2b with 1 equiv of NaIO4 resulted in efficient formation of 1a and 2a, which were isolated as purple and red solids, respectively. The EPR spectra of 1a showed pH dependency due to structural change of purine moiety.

Novel spirocyclization based on intramolecular 1, 4-addition and its asymmetric version have been developed using a combination of Lewis acid and 1, 2-diol. Treatment of five- and six-membered @a, @b-unsaturated cyclic ketones having a 4-oxopentyl group at the @b-position with Lewis acid and ethylene glycol gave spiro[4.5]decane-2, 7-dione and spiro[5.5]undecane-2, 8-dione, respectively. The asymmetric version of this reaction has been developed by using optically active 1, 2-diol such as cyclohexane-1, 2-diol to afford the spirocyclic products of up to 85% e.e.

Rh-Catalyzed intermolecular hydroacylation between salicylaldehydes and 1,5-hexadienes proceeded under remarkably mild reaction conditions to afford a mixture of iso- and normal-hydroacylated products in good yields. The experiments using deuterated salicylaldehyde-d revealed that “double chelation” of salicylaldehyde and 1,5-hexadiene to Rh-complex played vital roles in the catalytic cycle of intermolecular hydroacylation.

Elimination of the triflates (I) with the chiral base (‐)‐DPA yields the bicyclo(3.3.0)octenes (II) in high optical purity, whereas the way via the chiral ester (IV) and an achiral base is less promising.

The 2‐methoxycarbonylcycloalkanonecarboxylates (Ia), (Ic), and their cyanomethyl analogues (Ib) and (Id) undergo ring expansion upon treatment with tert‐butoxide, forming the 2,3‐disubstituted cycloalkanones (II).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Starting with the Grignard reagent (I) the synthesis of the title compound golfomycin A (VI) is described, the design of which is the result of mechanistic considerations concerning DNA‐cleaving and antitumor properties.

The hydroxyoxocyclopentenedicarboxylate (I) and the hydroxycyclopentanone (VI) react with the sulfonyl chloride (II) to give the sultones (III) ‐ (V) or (VII) and (VIII) and the dehydration product (IX).

Treatment of the 3‐(2‐acylethyl)cyclopentanones (I) with ethylene glycol (II) in the presence of boron trifluoride etherate results in cleavage and rearrangement processes, yielding the hydroxyethylcarboxylates (III) ‐ (V).

Treatment of the esters (I) according to A) does not give the expected product (III) but the rearrangement product (II) in addition to unchanged (I) and the retro‐Michael cleavage product.

1,4‐Addition of the organocopper reagents (II) to the unsaturated γ‐lactones (I) and (IV) forms enolates as intermediates which are trapped by intramolecular ring closure, yielding stereoselectively the bridged lactones (III) and (V).

The chiral phosphonates (III), prepared by the reaction of the ester (I) with the phosphonate (II), are coupled with the aldehydes (IV) to yield the unsaturated ketones (V).

The cyclopentanones (I) undergo ring expansion upon treatment with BF3etherate in ethyleneglycol (II) to yield the seven membered rings (III) and (IV).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Base‐catalyzed cyclization of the 1,4‐diketone (I) and subsequent oxidation during chromatography on silica gel produce enantiomeric mixtures of the regioisomeric cyclopentenones (II) and (III).

Treatment of the silver salt of trans‐3‐hexenedioic acid (I) with iodine results in cyclization, giving the bislactone (II).

Cyclization reaction of the 1,4‐diketones (I) gives the cyclopentenones (II) or the hydroxycyclopentenones (III) and (IV), depending on the conditions of the chromatographic work‐up.

Treatment of the carbocyclic diketo esters (I) and (III) with bases results in ring‐enlargement, producing the acetylcycloalkanonecarboxylates (II) and (IV).

The optical resolution of the endo‐acetate (I) is achieved using PFL.

Treatment of the 2‐(oxoalkyl)cycloalkanones (I), (III), (X), and (XIII) with boron trifluoride etherate and ethylene glycol results in the predominant formation of the bicyclic enones (II), (V), (XII), and (XV).

The bicyclic 1‐oxoalkyl ketones (I), (V), or (VIII) react with ethylene glycol (II) in the presence of boron trifluoride etherate to form mixtures of the spirocyclic hydroxyethyl esters (III), (VI), or (IX) and the tricyclic β,γ‐unsaturated ketones (IV), (VII), or (X).

The bicyclooctenyl sulfonates (Ia) and (Ib) with an optically active sulfonyl group undergo elimination upon reaction with tert‐butoxide to give the chiral title compounds (II) of only moderate optical purity.

The acylacetates (I) are coupled with the aldehydes (II), producing the pyrandiones (III).

(‐)‐Limonen‐10‐ol (I) is converted to the 11‐desoxyprostaglandin precursor (III) via the key intermediates (II).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.