从猪去氧胆酸甲酯表观合成角鲨多胺

以猪去氧胆酸甲酯为原料, 经15步反应以总产率5.6%表观合成具有抗菌、抗癌活性的海洋甾体角鲨多胺.     

猪去氧胆酸化学——Ⅳ.从猪去氧胆酸立体选择性合成熊去氧胆酸和鹅去氧胆酸的新法

本文报道以猪去氧胆酸甲酯(4b)为原料立体选择性合成熊去氧胆酸(1)和鹅去氧胆酸(3)的新方法。从猪去氧胆酸甲酯出发经8步反应得熊去氧胆酸(1),总收率26％。经7步反应得鹅去氧胆酸甲酯(3b),总收率31％。     

甾体植物生物调节剂的合成XXⅢ.'从猪去氧胆酸立体选择性合成牡蛎甾醇和油菜甾醇

牡蛎甾醇和油菜甾醇是从猪去氧胆酸所犁20-碳醛为起始物,各经六步反应合成的,总产率分别为48-57%和52-54%.合成的关键步骤是Claisen重排反应.     

甾体植物生物调节剂的合成XXⅢ.'从猪去氧胆酸立体选择性合成牡蛎甾醇和油菜甾醇

牡蛎甾醇和油菜甾醇是从猪去氧胆酸所犁20-碳醛为起始物,各经六步反应合成的,总产率分别为48-57%和52-54%.合成的关键步骤是Claisen重排反应.     

猪去氧胆酸化学7.(24R)-24,25-双羟基,(24R,25S)-24,25,26-三羟基和(25R)-25,26-双羟基胆固醇的立体选择性和区域选择性合成

本文报道以猪去氧胆酸甲酯(2a)为原料, 立体选择和区域选择性地合成了维生素D~3代谢产物及类似物的关键中间体(24O)-24,25-双羟基胆固醇(3b),(24O,25, 26-三羟基胆固醇(3c)和(25O)-25,26-双羟基胆固醇(3d).,总收率分别为27,27和38%.     

甾体植物生长激素的研究II:从猪去氧胆酸立体选择性合成(22S,23S)-香蒲甾醇

本文报道以猪去氧胆酸为原料,立体选择性地合成(SS2,23S)-香蒲甾醇,合成的关键步骤是用Li2Cu3(CH3)5立体专一地转化烯丙醇苯胺基甲酸酯10和13成为11和用OsO4-NMO在化合物16的不饱和侧链上立体选择性羟基化。     

甾体植物生长调节剂的研究——ⅩⅩ.从猪去氧胆酸立体选择性合成26,27-双失碳油菜甾醇内酯和26,27-双失碳香蒲甾醇

本文报道从猪去氧胆酸立体选择性地构成26,27-双失碳油菜甾醇内酯的侧链。关键步骤是20-碳醛化合物3与2-锂-2-异丙基1,3-二噻烷4的高立体选择反应,同时报道了26,27-双失碳香蒲甾醇11的合成,它是新化合物,它的生物活性正在测定之中。     

A Short and Highly Stereoselective Synthesis of Cerebrosterol

Ｃｅｒｅｂｒｏｓｔｅｒｏｌ (2 4Ｓ ｈｙｄｒｏｘｙｃｈｏｌｅｓｔｅｒｏｌ,1)ｆｏｒｍｅｄｉｎｓｍａｌｌａｍｏｕｎｔｓｉｎｈｕｍａｎａｎｄａｎｉｍａｌｂｒａｉｎ1ｆｒｏｍｃｈｏｌｅｓ ｔｅｒｏｌｉｓｉｍｐｏｒｔａｎｔｆｏｒｃｈｏｌｅｓｔｅｒｏｌｈｏｍｅｏｓｔａｓｉｓｉｎｔｈｉｓｏｒｇａｎ .Ｔｈｅｅｘｃｅｓｓｃｈｏｌｅｓｔｅｒｏｌｉｓｃｏｎｖｅｒｔｅｄｉｎｔｏ 2 4Ｓ ｈｙｄｒｏｘｙ ｃｈｏｌｅｓｔｅｒｏｌｂｙａｕｎｉｑｕｅｂｒａｉｎ ｓｐｅｃｉｆｉｃ 2 4Ｓ ｈｙｄｒｏｘｙｌａｓｅ ,ｗｈｉｃｈｃｏｕｌｄｂｅｒ…     

Stereoselective Synthesis of Tetrahydropyran D-Ring of Methyl Sartortuoate

A stereoselective synthesis of functionalized tetrahydropyran D‐ring of methyl sartortuoate ( 1 ) was achieved starting from geraniol in a high yield. Sharpless asymmetric kinetic resolution, asymmetric dihydroxylation as well as asymmetric epoxidation were applied as key steps to establish all the four stereocenters of the D‐ring.     

Simple Approach to the Highly Stereoselective Synthesis of trans-1,2-Cyclopropane Derivatives

In the presence of KF·2H2O, furoylmethyltriphenylarsonium bromide （1a） or thienoylmethyltriphenylarsonium bromide （1b） reacted with 2-[（un）substituted benzylidene]malononitrile （2） in chloroform at room temperature to give trans-3,3-dicyano-1-furoyl-2-[（un）substituted phenyl]cyclopropane （3a） or trans-3,3-dicyano-1-thienoyl-2- [（un）substituted phenyl]cyclopropane （3b） respectively in good yield with high stereoselectivity. The structures of product 3 were confirmed by IR, MS, 1^H NMR, 1^H-1^H COSY and microanalysis. The relative configuration of product 3 was determined by 1^H-1^H NOESY technique. The mechanism for the formation of product 3 was also proposed.     

A stereoselective synthesis of squalamine

Squalamine (1) was synthesized stereoselectively in 14 steps and 19% overall yield from 3-keto-5-chenodeoxycholanate (2) by using a modified Sharpless asymmetric dihydroxylation as the key step.     

Stereoselective Total Synthesis of Chrysanthemol

Recently,muchattentionhasbeenpaidtothesynthesisofbioactivenaturalproducts.Chrysanthemol,aneudesmanetypesesquiterpene,firstisolatedfromChrysanthemumindicumL.byD.Q.Yuetal.',showedstrongantiinflanunatoryactivityinmice.ThestructureandabsolutestereochemistryofchrVsanthemolwereelucidatedas1ThesyntheticrouteofchrysanthemolflomR-( )-carvoneisdepictedinScheme1:n.50%aqACOH,2hr;d)KOH,EtOH,oOC,3hr,e)Na,propanol,50"C,6hr,67.2%;66.7%i)m-CPBA/NaHCO3,CHZC12,r.t.,3.5hr,84%;TreatmentofR-( )-carvon…     

Novel Stereoselective Synthesis of 4-Acetoxyazetidinone from Methyl 6,6-Dibromopenicillanate: Key Intermediate for the Preparation of Carbapenem Antibiotics

A novel and practical process for the completely stereoselective synthesis of carbapenem key intermediate (3R,4R)-4-acetoxy-3-[(R)-1-((t-butyldimethylsilyl)oxy)ethyl]-2-azetidinone has been developed by starting from methyl 6,6-dibromopenicillanate. Aldol condensation of the magnesium enolate derived from the β-sulfoxide with acetaldehyde allows for the stereospecific introduction of a 1-R-hydroxyethyl substituent as C-6. The hydroxyethylated product was reduced with Zn-NH₄OAc in tetrahydrofuran (THF) efficiently to give methyl 6-(1-hydroxyethyl)-penicillanate-1β-oxide. Protection of the hydroxy group followed by treatment with 2-mercaptobenzothiazole afforded the dithioazetidinone, which was easily reduced and methylated to give 4-methylthioazetidinone. Then this compound was oxidized with permanganate to selectively remove the side chain at the N-position to afford the 4-methylthioazetidinone derivative. A facile conversion of the methylthio group to acetoxy for a practical synthesis of 4-acetoxyazetidinone was also reported. This method provided an efficient and cost-effective process with good overall yield and excellent stereoselectivity.     

Stereoselective Synthesis of 2-Deoxythiosugars from Glycals

2-deoxythiosugars are more stable than 2-deoxysugars occurring broadly in bioactive natural products and pharmaceutical agents. An effective and direct methodology to stereoselectively synthesize α-2-deoxythioglycosides catalyzed by AgOTf has been developed. Various alkyl thiols and thiophenols were explored and the desired products were formed in good yields with excellent α-selectivity. This method was further applied to the syntheses of S-linked disaccharides and late-stage 2-deoxyglycosylation of estrogen, L-menthol, and zingerone thiols successfully.