Tributylchlorostannane as Lewis Acid in the Regioselective Reductive Cleavage of Ketals

A regioselective reductive demethoxylation of dimethyl and mixed ketals, using sodium cyanoborohydride in the presence of a catalytic amount of tributylchlorostannane as Lewis acid in refluxing tert-butanol is described

Tri-n-butylstannyl chloride-sodium cyanoborohydride mediated regioselective reductive demethoxylation of alkyl methyl ketals

A regioselective reductive demethoxylation of alkyl methyl ketals employing sodium cyanoborohydride in the presence of a catalytic amount of tri-n-butyltin chloride as Lewis acid is described

Tributylchlorostannane as Lewis acid in the regioselective reductive cleavage of ketals

A regioselective reductive demethoxylation of dimethyl and mixed ketals, using sodium cyanoborohydride in the presence of a catalytic amount of tributylchlorostannane as Lewis acid in refluxing tert-butanol is described

Chiral synthons from carvone .20. Stereo- and enantiospecific total synthesis of (-)-valeranone

Stereo- and enantiospecific total synthesis of the irregular sesquiterpene, valeranone, starting from S-6-methylcarvone employing a hydrindanone to decalone ring expansion methodology, is described

Enantiospecific total syntheses of (-)-valeranone

1265-1274Two convenient methodologies have been described for the enantiospecific synthesis of (—)-valeranone 1. The hydrindanone 12, obtained from the readily and abundantly available monoterpene (R)-carvone, has been converted into the ketoaldehyde 16 via the alkene 15b. In another direction the lactone 18,obtained from the hydrindanone 12, has been elaborated into the ketoaldehyde 16 employing two methodologies. Intramolecular aldol condensation followed by hydrogenation transformed the ketoaldehyde 16 into (—)-valeranone 1

A New Tetrahydrofurannulation Via Tandem Radical Cyclization Reaction-Reductive Deoxygenation Sequence

Treatment of bromoketals 2, derived from allyl alcohols 1, with tributyltin chloride, sodium cyanoborohydride and AIBN furnishes the tetrahydrofurannulated products 3 via a 5-exo-trig radical cyclisation reaction followed by reductive cleavage of ketal 4

Enantiospecific total syntheses of (-)-valeranone

Two convenient methodologies are described for the enantiospecific synthesis of (-)-valeranone. The hydrindanone I, obtained from the readily and abundantly available monoterpene (R)-carvone, was converted into the ketoaldehyde II via an alkene. In another direction the lactone III, obtained from the hydrindanone I, has been elaborated into the ketoaldehyde II employing two methodologies. Intramol. aldol condensation followed by hydrogenation transformed the ketoaldehyde II into (-)-valeranone

Cyclopentaannulation of allyl alcohols via a radical cyclisation reaction. Total synthesis of 4-epibakkenolide-A

A four step cyclopentaannulation methodology starting from allyl alcohols using 5-exo-trig radical cyclisation as the key reaction, and its application to the total synthesis of 4-epibakkenolide is described

Tributyltin chloride-sodium cyanoborohydride mediated tandem radical cyclisation-reductive demethoxylation sequence

Reaction of the bromoketals 3, 7a-g and 11 with tri-n-butyltin chloride and sodium cyanoborohydride in the presence of a catalytic amount of AIBN furnished the ethers 5, 8a-g and 13 via a tandem sequence comprising of a radical cyclisation reaction and tri-n-butylhalostannane and sodium cyanoborohydride mediated reductive demethoxylation of the resulting cyclic ketals

A radical cyclisation based cyclopentenone annulation of allyl alcohols

A four-step cyclopentenone annulation reaction of allylic alcohols employing a 5-exo-trig radical cyclisation reaction of mixed allyl methyl ketals of bromoacetone as the key step is described. The annulated product 12b obtained from 2,3-dimethylcyclohexenol has been further elaborated into (±)-epibakkenolides employing a 5-exo-dig radical cylisation reaction based α-spiro-β-methylene-γ-butyrolactone annulation methodology