M. Gill

Cyclopentamoids from phenol. Part VII. Preparation and reactions of a 3-hydroxy-5-oxocyclopent-1-enyl carbanion equivalent

Abstract (3 S * , 5 R * )-1-Lithio-5-( t -butyldimethylsilyloxy)-3-(tetrahydropyran 2-yloxy)cyclopent-1-ene (7) is prepared from phenol via the chlorocyclopentenone (1) and the stannylcyclopentenediol derivative (6); this latent 3-hydroxy-5-oxocyclopent-1-enyl carbanion (7) reacts efficiently with various electrophiles to form substituted cyclopentenediol derivatives (8) which can be converted into the corresponding 2-substituted 4-hydroxycyclopent-2-enones (9).

Cyclopentanoids from phenol. part iii. synthesis of chiral 4-hydroxycyclopent-2-enones☆

Abstract Chiral 4-hydroxycyclopent-2-enones (1 and 2), of which the ( R )-enantiomers are important intermediates in prostanoid synthesis, are readily prepared in optically pure form from phenol via reduction of the corresponding 3-chloro-4-t-butyldimethylsilyloxycyclopent-2-enones (5 and 3).

3-[(7Z-Hexadecenyli-4-methylfuran-2,5-dione from Piptoporus australiensis

Abstract The structure of a new citraconic anhydride derivative from Piptoporus australiensis is established by spectroscopic and chemical methods as 3-[(7Z-hexadecenyl]-4-methylfuran-2,5-dione.

Cyclopentanoids from phenol—9 : 3-Alkyl- and 3-alkenyl-5-hydroxycyclopent-2-enones☆

Abstract An efficient and versatile synthesis of 3-alkyl- and 3-alkenyl-5-hydroxycyclopent-2-enones is described. The key intermediate, 4-(t-butyldimethylsilyloxy)-3-methoxycyclopent-2-enone (5), is prepared in five steps from phenol. 1,2-Addition of various organolithium and Grignard reagents yields tertiary alcohol intermediates which afford the title compounds after solvolysis and desilylation.

Synthesis of chiral prostanoid intermediates from phenol

The 2-substituted derivatives of (4R)-4-hydroxycyclopent-2-enone (11) and (12), important intermediates in prostaglandin synthesis, are prepared from (4S)-3-chloro-4-(dimethyl-t-butylsilyloxy)cyclopent-2-enone (4) which is available in five steps from phenol.

New chemistry of iminyl radicals

Aryliminyls, produced by oxidation of oximino-acetic or -propanoic acids with persulphate, may either dimerise, cyclise on to an adjacent phenyl group to give a phenanthridine, or abstract hydrogen from an o-methyl group to give a benzyl radical.

Synthetic reactions with iminyl radicals

Aryl(triarylvinyl)iminyls readily cyclise to quinolines while isopentyl-, butyl-, and propyl-(phenyl) iminyls yield tetralones by intramolecular hydrogen abstraction followed by cyclisation of the ensuing alkyl radicals.