R. F. Valeev

Synthesis and some transformations of (−)-carveol

Reduction of the oxo group in (−)-carvone with LiAlH4, NaBH4, and (i-Bu)2AlH was performed. It was found that the reduction with the system CeCl3 · 7 H2O-NaBH4 in methanol at 20°C is the most practical procedure for the synthesis of (−)-carveol. Solvolysis of (−)-carvyl methanesulfonate gave products of SN2 and SN2′ replacement of the methylsulfonyloxy group, the latter slightly prevailing. Overman rearrangement of (−)-carveol resulted in the formation of the corresponding trichloroacetamide derivative, and intramolecular iodoetherification of the title compound afforded 6-iodomethyl-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-ene.

New orthogonally functionalized synthetic blocks from R-(−)-carvone

The intramolecular cyclization of (−)-cis-carveol under iodine treatment afforded (1R,5R,6S)-6-iodomethyl-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-ene that was subjected to allyl oxydation with the complex CrO3DMP giving a synthetically valuable building block, (1R,5R,6S)-6-iodomethyl-2,6-dimethyl-7-oxabicyclo[3.2.1]oct-2-ene-4-one. In the latter the double bond was cleaved by ozonization to obtain the expected trioxo derivative, and the subsequent ozonolysis of its enol form provided a multiple functionalized tetrahydrofuran derivative.

Building blocks for (C15−C3)-modified epothilone D analogs

A promising potentially biologically active structure have been designed by isosteric rearrangement of the C15−C3 fragment of epothilone D, and building blocks necessary for its assembly have been synthesized.

Oxidation of (1S,5R,7R,S)-(4,7-dimethyl-6-oxabicyclo[3.2.1]oct-3-en-7-yl) methanol with pyridinium chlorochromate

The oxidation of (1S,5R,7R,S)-(4,7-dimethyl-6-oxabicyclo[3.2.1]oct-3-en-7-yl)methanol epimeric at the C7 atom resulted in scalemic (5R)-5-acetyl-2-methylcyclohex-2-en-1-one.

Synthesis of 6-Hydroxycarvone Derivatives and Their Oxidative Decyclization with Lead Tetraacetate

Abstract6-Hydroxy derivatives of R-(−)-carvone and 7,8-epoxycarvone were synthesized and subjected to oxidative ring cleavage by the action of lead tetraacetate. These reactions followed different patterns, depending on the substrate structure.

Carvone hydrochloride in the synthesis of thiazole-containing C11–C21-block of epithilones gem-dimethylcyclopropane analogs

Starting with R-(−)-carvone hydrochloride a synthesis was developed of the key chiral block for the epothilones gem-dimethylcyclopropane analog.

Synthesis of a chiral block for С 1 –С 5 fragment of epothilones

Synthesis was developed of a new chiral block for epothilone analogs from R-(‒)-pantolactone.

Synthesis of a chiral building block for the C6‒C9 fragment of epothilones

A procedure has been developed for the synthesis of a new chiral building block for epothilone analogs starting from L-malic acid.

Alternative synthesis of thiazole-substituted fragment C10-C21 of epothilone D analog

New procedure was developed for preparation of the fragment C10-C21 of epothilone D analog from R-(-)-carvone. The key stage of the synthesis consists in the regio- and stereoselective Wittig reaction of (5R)-5-acetyl-2-methylcyclohex-2-en-1-one with an ylide generated from tributyl[(2-methylthiazol-4-yl)methyl]-phosphonium chloride.

Chiral furan-2-yl-substituted reagents based on (+)-α-methylbenzylamine

The Schiff base obtained by condensation of furfural with (+)-α-methylbenzylamine was reduced with sodium tetrahydridoborate, and the resulting amine was alkylated with methyl iodide to obtain the corresponding chiral tertiary amine. Oxidation of the reduction product with m-chloroperoxybenzoic acid gave (1R)-N-(furan-2-ylmethylidene)-1-phenylethanamine N-oxide.