Latif Kelebekli

Synthesis of a new class of aminocyclitol analogues with the conduramine D-2 configuration.

Summary A new class of aminocyclitol derivatives with the bicyclo[4.2.0]octane skeleton was synthesized starting from cyclooctatetraene. Photooxygenation of trans-7,8-diacetoxy- and cis-7,8-dichlorobicyclo[4.2.0]octa-2,4-diene afforded the bicyclic endoperoxides. Reduction of the latter with thiourea followed by a Pd(0) catalyzed ionization/cyclization reaction gave the corresponding oxazolidinone derivatives. Oxidation of the double bond with KMnO4 or OsO4 followed by acetylation gave the acetate derivatives, the exact configuration of which was determined by spectroscopic methods. Hydrolysis of the oxazolidinone rings and removal of the acetate groups furnished the desired aminocyclitols.

Synthesis and characterisation of 2,3a,5,6,7a-pentaacetoxy-octahydro-1H-indene from indan-2-ol

A synthesis of 2,3a,5,6,7a-pentaacetoxyoctahydro-1H-indene has been achieved starting from indan-2-ol. The Birch reduction of indan-2-ol gave 4,7-dihydro-2-indanol in high yield which when followed by acetylation, resulted in the corresponding acetates. The OsO4 oxidation of the 2-acetoxy-4,7-dihydroindane followed by acetylation furnished the desired pentaacetates in high yield.

Synthesis and characterisation of 2,3,4a,6,8a-penta-acetoxy decahydronaphthalene from 1,2,3,4-tetrahydronaphthalen-2-ol

2,3,4a,6,8a-Penta-acetoxy decahydronaphthalene has been synthesised starting from 1,2,3,4-tetrahydronaphthalen-2-ol. The Birch reduction of 1,2,3,4-tetrahydronaphthalen-2-ol gave a high yield of 1,2,3,4,5,8-hexahydronaphthalen-2-ol which was acetylated. The OsO4 oxidation of the 1,2,3,4,5,8-hexahydronaphthalen-2-yl acetate followed by further acetylation gave the pentaacetates.

Regio- and stereospecific synthesis of a new benzoconduritol-C derivative

A stereospecific synthesis of 3-(2-bromophenoxy)-1,2,3,4-tetrahydronaphthalen-1,2,4-triol (benzoconduritol-C derivative) has been achieved by a fully regio- and stereospecific rhodium catalysed reaction of oxabenzonorbornadiene in the presence of 2-bromophenol.

Stereospecific synthesis of 1,4-di-O-methyl-myo-inositol (liriodendritol)

1,4-di-O-methyl-myo-inositol, a natural product, was synthesised starting from p-benzoquinone. The treatment of 5,6-dibromocyclohex-2-ene-1,4-diol with Na/ROH-system afforded a C2-symmetric conduritol-B derivative key intermediate followed by acetylation. The OsO4 oxidation and followed by acetylation gave the tetraacetates. The hydrolysis of the acetate groups furnished the desired the myo-inositol derivatives in high yield.

Synthesis, characterization, and crystal structure of 6,7a-dichloro-3a-hydroxyoctahydro-1H-indene-2,5-diyl diacetates

The first syntheses and characterizations of 6,7a-dichloro-3a-hydroxyoctahydro-1H-indene-2,5-diyl diacetates were successfully obtained starting from indan-2-ol. Epoxidation of 2 was carried out using mCPBA in methylene chloride followed by acetylation using acetyl chloride to furnish the diacetates. The structures of all synthesized compounds were characterized by spectroscopic methods.

(1SR,2SR,3SR,4RS,5RS,6RS,7SR,8RS)-7,8-Dichloro­bicyclo­[4.2.0]octa-2,3,4,5-tetrayl tetra­acetate

In the title compound, C(16)H(20)Cl(2)O(8), the bicyclic system contains a central non-planar cyclohexane ring which is fused to a cyclobutane moiety. The cyclohexane ring has a chair conformation and the whole system adopts a syn conformation. The structure provides information on the stereochemical course of the chlorination, photo-oxidation and hydroxylation steps of the reaction.

Direct Synthesis of trans-1,4-Diacetoxycyclohexa-2,5-diene by Electrochemical Reduction of r-1,t-4-Diacetoxy-t-2,c-3-dibromocyclohex-5-ene

Electrochemical reduction of r-1,t-4-diacetoxy-t-2,c-3-dibromocyclohex-5-ene 1 gives only trans-1,4-diacetoxycyclohexa-2,5-diene 2 in good yield while the commonly used Zn reduction gives a product mixture containing 2 and acetoxybenzene 3 derived from acetoxy elimination.