Phillip A. Zoretic

Stereospecific tetracyclization of icosatetraenes via Mn(III) promoted oxidative free-radical cyclization

Abstract A stereospecific oxidative free-radical cyclization of polyene 10a to the D-homi-5α-androstane system 11a containing seven asymmetric centers is reported.

A biomimetic-like radical approach to furanoditerpenes

Abstract A highly stereoselective oxidative free-radical cyclization of polyene 9 has been demonstrated as a one step entry to a complex tricarbocyclic synthon 10 which contains five crucial stereogenic centers. An entry to the spongian and marginatane furanoditerpenes has been realized from synthon 10 .

Spongian furanoditerpenes: An intramolecular radical approach

Abstract An oxidative free-radical cyclization of polyene 3 , derived from farnesyl acetate, has been utilized in the construction of 4 containing six chiral centers. The direct conversion of 4 to the intact spongian skeleton 9 is also reported.

Aspects of Manganese (III) - Promoted Oxidative Free Radical Cyclizations to Functionalized Bicyclic Systems

Abstract The stereospecific formation of trans-decalin 7 from oxidative radical cyclization of 6 and formation of functionalized bicyclic systems from radical cyclization of 3 are detailed.

An Oxidative Free-Radical Cyclization Approach to d,1-Δ8-14-Epiestrone-3-methyl Ether

Abstract A Stereospecific free-radical cyclization of β-keto esters 4 and 5 to cis-hydrindanones 9 and 6, respectively, and conversion of 6 to d, 1–14-epiestrone intermediate 8 are reported.

A radical prototype to steroids: Synthesis of d,l-5α-D-homoandrostane-4α-methyl-3,17a-dione

An intramolecular radical methodology is described as an approach to D-homoandrostanes. The angular C-8 cyano group in tetracycle 7 derived from radical cyclization of polyene 6 serves as a latent functional group for elaboration to the C-8 βH in d,l-homoandrostane 11.

Total synthesis of d,1-megaphone

Abstract The Synthesis of racemic megaphone 1 , a cytotoxic neolignan, is described.

An intramolecular radical approach to angular electrophores in polycyclic systems

Abstract The introduction of an angular C-8 cyano group in polycyclic system 9 has been realized via a stereoselective oxidative radical cyclization of polyene 8 containing an α,β-unsaturated electrophore.

Intramolecular Free-Radical Cyclization An Approach to Hydrindanone Systems

Abstract A SmI2 promoted cyclization of the keto aldehydes 6 in the presence of tetraglyme to afford trans -7a-methyl-1,5-hydrindanedione is reported.

A Stereooontrolled Approach to Tri and Tetrasubstttuted Cyclohexanones

Abstract A series of reactions utilizing acetals 2–5 with organo cuprates was studied to determine the stereoselectivity of the 1,4-conjugate addition. A90:10 stereoselectivity was observed from the reaction of lithium or bromomagnesium divinyl cuprate with acetal 5 which generated a facile entry to the tetrasubstituted cyclohexanone via a consecutive 1,4-conjugate addition - 1,3-alkylation sequence.