An Alternative Synthesis of 1,1′-Bis-valienamine from <scp>d</scp>-Glucose
作者:Tony K. M. Shing、Hau M. Cheng
DOI:10.1021/jo100474p
日期:2010.5.21
An alternative synthesis of 1,1′-bis-valienamine 5, which was demonstrated to be a potent trehalase inhibitor, has been achieved from d-glucose in 12 steps with 15% overall yield via enone 12 as the key intermediate, involving a direct aldol reaction of a glucose-derived diketone and a palladium-catalyzed allylic coupling reaction as the keysteps.
The Structure and Stereochemistry of Gabosine K: Syntheses of 7-O-Acetylstreptol and 7-O-Acetyl-1-epi-streptol
作者:Tony Shing、Hau Cheng
DOI:10.1055/s-0029-1218540
日期:2010.1
Gabosine K, whose structure was erroneously assigned previously as 7-O-acetyl-4-epi-streptol, has been synthesized for the first time from d-glucose via a key carbocyclization strategy, intramolecular direct aldol reaction of a 2,6-diketone, in 15 steps with 13.5% overall yield. In the same manner, (+)-7-O-acetyl-streptol has been constructed for NMR spectral comparison. The structure, relative and absolute configurations of (-)-gabosine K are now revised and established as (-)-7-O-acetyl-1-epi-streptol, that is, (1R,2S,3S,4R)-tetrahydroxy-5-acetoxymethylcyclohex-5-ene. Since the specific rotation of the natural product is not available, the absolute configuration of natural gabosine K is either (-)-7-O-acetyl-1-epi-streptol or its enantiomer.
Gabosine K 的结构以前被错误地归类为 7-O-acetyl-4-epi-streptol ,该化合物是通过一种关键的碳环化策略--2,6-二酮的分子内直接醛醇反应--首次从 d-葡萄糖中合成的,共经过 15 个步骤,总收率为 13.5%。以同样的方式,还构建了 (+)-7-O- 乙酰基链烷醇,用于核磁共振光谱比较。(-)-gabosine K 的结构、相对构型和绝对构型现已修订并确定为 (-)-7-O-乙酰基-1-epi-链醇,即 (1R,2S,3S,4R)-四羟基-5-乙酰氧甲基环己-5-烯。由于无法获得天然产物的特定旋转,因此天然棉子碱 K 的绝对构型是 (-)-7-O- 乙酰基-1-epi-链醇或其对映体。
Facile syntheses of (+)-gabosines A, D, and E
作者:Tony K. M. Shing、Hau M. Cheng
DOI:10.1039/b911810a
日期:——
and E (5), which share the same trihydroxycyclohexenone skeleton, were synthesized from enone 11 as the common intermediate. The key building block 11 was accessed by an intramolecular aldolcyclization of a diketone derived from D-glucose (8).
Intramolecular Direct Aldol Reactions of Sugar Diketones: Syntheses of Valiolamine and Validoxylamine G
作者:Tony K. M. Shing、Hau M. Cheng
DOI:10.1021/ol801889n
日期:2008.9.18
A new and stereoselective intramolecular direct aldol reaction of diketones derived from carbohydrates has been developed to construct carbocycles with D-gluco-, D-galacto-, D-manno-, and L-ido-configurations. The stereochemical outcome of the aldol reaction of the diketone is dependent on the base used. Transformation of D-gluco-aldols readily affords valiolamine which also constitutes a formal synthesis
Enantiospecific Synthesis of Pseudoacarviosin as a Potential Antidiabetic Agent
作者:Tony K. M. Shing、Hau M. Cheng、Wai F. Wong、Connie S. K. Kwong、Jianmei Li、Clara B. S. Lau、Po Sing Leung、Christopher H. K. Cheng
DOI:10.1021/ol8010503
日期:2008.7.17
A pseudo-1,4'- N-linked disaccharide, pseudoacarviosin 5, was constructed via a key palladium-catalyzed coupling reaction of pseudoglycosyl chloride 8 (prepared from d-glucose via a novel direct intramolecular aldol addition in 12 steps) and pseudo-4-amino-4,6-dideoxy-alpha- d-glucose 9 (prepared from l-arabinose via an unusual trans-fused isoxazolidine-selective intramolecular nitrone-alkene cycloaddition