Zhaoming Xiong

An efficient stereocontrolled synthesis of (−)-10-epi-5β,11-dihydroxyeudesmane and (−)-4,10-epi-5β,11-dihydroxyeudesmane

Abstract A concise and efficient synthesis of (−)-10-epi-5β,11-dihydroxyeudesmane 1 and (−)-4,10-epi-5β,11-dihydroxyeudesmane 2, via (−)-10-epi-γ-eudesmol 5, was accomplished starting from (+)-dihydrocarvone. The salient feature of our synthesis is the utilization of substrate-directable epoxidation and homogeneous hydrogenation to control the stereochemistry at the C-4 and C-5 positions of the title compounds.

First enantioselective total synthesis of glutinone and its C(7) and C(11) epimers

Abstract A facile and efficient asymmetric synthesis of glutinone 1 and its C(7) and C(11) epimers 1b – d is presented, using the Sharpless asymmetric dihydroxylation reaction as the key step. By comparing the spectral data of the natural product with that of the synthetic samples, we could confirm the absolute configuration of glutinone 1 .

Total synthesis and stereochemistry of 13-hydroxy-α-eudesmol

Abstract The first total synthesis of both C-11 epimers of 13-hydroxy-α-eudesmol 1a and 1b by the use, as a key reaction, of the Sharpless asymmetric dihydroxylation of alkene 7 is presented. The absolute configuration of natural 13-hydroxy-α-eudesmol is established through comparison of the 1 H NMR spectrum of natural diol and synthetic diols. In our synthesis another natural product (+)-α-selinene 2 has also been accomplished.

First Synthesis of (+)-5α-Hydroxy-β-selinene and (–)-5β-Hydroxy-β-selinene

A facile and efficient synthesis of (+)-5α-hydroxy-β-selinene 1 and (–)-5β-hydroxy-β-selinene 2 starting from (+)-dihydrocarvone has been carried out.

A Facile Total Synthesis of (±)-Selina-3, 11-Dien-9-Ol

Abstract A facile total synthesis of (±)-selina-3, 11-dien-9-ol (1) has been described. The key step is the one-pot reductive deoxygenation of α, β-unsaturated p-tosylhydrazone and reduction of 9-carbonyl of 9 with sodium borohydride.

First Total Synthesis of 3α,4α-Oxidoagarofuran and (-)-3β,4α-Dihydroxy-β-dihydroagarofuran

Abstract The first stereoselective total synthesis of (–)-3β, 4α-dihydroxy-β-dihydroagarofuran (1) and 3α, 4α-oxidoagarofuran (2) has been described. The key step is the epoxidation of α-agarofuran (6) with dimethyldioxirane.

Studies on the Dehydrogenation of 9-Oxygenated-eudesma-4-en-3-ones with DDQ

Abstract 9-Acetoxy-eudesma-4, 11-dien-3-ones (4a, 4b) and 9-acetoxy-14-noreudesma-4, 11-dien-3-ones (5a, 5b) were treated with DDQ in dioxane to yield normal 1,2-dehydro-products, whereas 14-noreudesma-4, 11-dien-3, 9-diones (2a, 2b) afforded a rearranged aromatic product, 1-hydroxy-15-noreudesma-1, 3, 5 (10), 11-tetraen-9-one(3). No reaction was observed by treatment of eudesma-4, 11-dien-3, 9-diones (1a, 1b) with DDQ under the same conditions. The effect of 10-methyl configuration on this reaction is also discussed.

A Facile Synthesis of 3-Oxo-7αH-eudesma-4-en-9β,12-diol

Abstract A facile synthesis of a mixture of the C-11 isomeric 3-oxo-7αH-eudesma-4-en-9β, 12-diol has been achieved from oxycarvone. The C-11 configuration of natural product is established through comparison of 1H NMR spectra between synthetic 1b, or the mixture of 1a and 1b, and natural diol.

THE ENANTIOSELECTIVE SYNTHESIS OF (+)-SELINA-3, 11-DIEN-9-OL

Abstract The title compound 1 was enantioselectively synthesized from oxycarvone in nine steps with an overall yield of 15%. The key step involves the p-toluenesulfonhydrazide assisted diastereoselective reductive rearrangement of allylic alcohol.

Facile Synthesis of 6β-Hydroxy-(7αH)-eudesm-4-en-3-one and β-Cyperone

A stereoselective total synthesis of 6β-hydroxy-(7αH)-eudesm-4-en-3-one 1 and β-cyperone 12 starting from (+)-dihydrocarvone 7 is described.