An Enamide‐Based Domino Reaction for a Highly Stereoselective Synthesis of Tetrahydropyrans

A novel method for the highly stereoselective synthesis of tetrahydropyrans is reported. This domino reaction is based on a twofold addition of enamides to aldehydes followed by a subsequent cyclization and furnishes fully substituted tetrahydropyrans in high yields. Three new σ‐bonds and five continuous stereogenic centers are formed in this one‐pot process with a remarkable degree of diastereoselectivity. In most cases, the formation of only one out of 16 possible diastereomers is observed. Two different stereoisomers can be accessed in a controlled fashion starting either from an E‐ or a Z‐configured enamide.     

Synthesis of 2,4,6,8-Tetrasubstituted 1,5-Naphthoquinones

Derivatives of N-aryl-5-hydroxy-1,4-naphthoquinone 4-imines react with primary amines to afford 2,4,6,8-tetrasubstituted 1,5-naphthoquinones.     

Facile Stereoselective Approach to Diverse Spiroheterocyclic Tetrahydropyrans: Concise Synthesis of (+)‐Broussonetine G and H

A highly diastereoselective copper‐catalyzed multicomponent cyclization of exocyclic enol ethers/enamines with methylene malonate and aldehydes has been developed to furnish spiroheterocyclic tetrahydropyrans in high yields with greater than 95:5 d.r. This method is practical, in that 36 examples, including a range of aldehydes and exo‐vinyl heterocycles, are presented. By applying the newly developed method, the total synthesis of (+)‐broussonetine G and formal synthesis of (+)‐broussonetine H were achieved in a concise way.     

3-卤氧化吲哚参与胺基化反应合成3-胺基四取代氧化吲哚

以3-卤氧化吲哚为起始原料,DMAP为有机催化剂,在甲苯中于60 ℃和苄胺发生3-胺基化取代反应后,用Boc基团对氮原子进行保护,合成了7个新型的N-Boc-3-胺基四取代氧化吲哚,收率85%~93%,其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征。     

Synthesis of 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyldibutyl phosphite

Conclusions The condensation of 2,3,4,6-tetra-O-acetyl--D-glucopyranose with dibutylacetyl phosphite proceeds without inversion of the configuration, forming 2,3,4,6-tetra-O-acetyl--D-glycopyranosyldibutyl phosphite.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2207–2208, December, 1966.     

Synthesis of deuterated methyl 2,3,4,6-Tetra-o-methyl-β-d-galactopyranosides

Conclusions We have synthesized methyl 2,3,4,6-tetra-O-methyl--D-galactopyranosides selectively labeled with deuterium in positions 1–6 with deuterium content >90%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 192–195, January, 1978.     

1,2,4,6—四取代吡啶氟硼酸盐的合成及其植物生长调节活性

合成了一系列四取代吡啶氟硼酸盐，有些对水稻和绿豆显示出良好的抑制生长的活性。     

1，2，4，6－四取代吡啶氟硼酸盐的合成及其植物生长调节活性

合成了一系列四取代吡啶氟硼酸盐，有些对水稻和绿豆显示出良好的抑制生长的活性。     

新型甘油拼接3-四取代氧化吲哚的无催化剂无溶剂合成

以3-氯氧化吲哚为原料,在无催化剂、无溶剂条件下于80 ℃发生亲核取代反应,合成了10个新型的甘油拼接3-四取代氧化吲哚,收率54%~72%, dr值10/9~>10/7, 其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征。     

Rhodium-Catalyzed Cyclization of Terminal and Internal Allenols: An Atom Economic and Highly Stereoselective Access Towards Tetrahydropyrans

A comprehensive study of a diastereoselective Rh-catalyzed cyclization of terminal and internal allenols is reported. The methodology allows the atom economic and highly syn-selective access to synthetically important 2,4-disubstituted and 2,4,6-trisubstituted tetrahydropyrans (THP). Furthermore, its utility and versatility are demonstrated by a great functional-group compatibility and the enantioselective total synthesis of (−)-centrolobine.     

L-苏式二氢鞘氨醇的立体选择性合成

二氢鞘氨醇（ＤＨＳ）是２－氨基－１，３－二羟基的饱和长链氨基醇化合物，是构成鞘脂类（包括鞘磷脂和糖鞘脂）的主链部分．由于鞘脂类在自然界中来源稀少，又很难得到纯品．因此，作为鞘脂类主链部分的二氢鞘氨醇的合成有重要的意义［１］．二氢鞘氨醇有两个手性碳，共...     

Synthesis of N-Glycyl-2,3,4,6-tetra-O-benzyl-1,5-dideoxy-1,5- imino-D-glucitol

1-Deoxynojirimycin (1,5-dideoxy-1,5-imino-D-glucitol, DNJ) and its derivatives have been found to have a number of biological activities, such as anti-HIV, anticancer, anti-diabetic, etc.[1] N-Hydroxylethyldeoxynojirimycin (Miglitol)has been used as a drug for treating diabetic. N-Butyl-1-deoxynojirimycin (NB-DNJ) has show potent anti-HIV-1 and HIV-2 activity without cytotoxicity.[2] Recently, NB-DNJ has been approved for clinical trials as a potential therapy for some glycosphingolipid (GSL) lysosomal storage diseases, which belong to a group of severe and fatal human diseases[3]Therefore, it is very significant to study N-substituted compounds of DNJ.     

Synthesis of deutero analogs of α-methyl-2,3,4,6-tetra-O-methyl-D-glucopyranoside

Conclusions The 1d-, 2d-, 3d-, 4d-, 5d-, and 6d₂--methyl-2,3,4,6-tetra-O-methyl-D-glucopyranosides, containing over 90% of deuterium were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 201–204, January, 1977.     

Synthesis of 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto)pyranosylcaprolactams and 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto) pyranosylpyrrolidones

A new synthesis of certain lactam-containing N-glycosides was developed. 2,3,4,6-Tetra-O-acetyl-β-D-gluco(galacto)pyranosylcaprolactams and 2,3,4,6-tetra-O-acetyl-β-D-gluco(galacto)pyranosylpyrrolidones were synthesized by condensation at room temperature of acetobromoglucose and acetobromogalactose with ɛ-caprolactams and α-pyrrolidone. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 105–106, March–April, 2006.     

Stereoselective Synthesis of Trisubstituted Olefins

Abstract

A new method for the highly stereoselective synthesis of trisubstituted olefins is. presented. The method involves the stereoselective construction of various β-hydroxy phosphonamidates followed by their thermolysis to provide trisubstituted olefins in extremely high geometrical purity (>99/1).     

立体选择性合成内型N-Boc-N-去甲托品醇

以托品酮为起始原料,与氯甲酸氯乙酯经脱甲基化反应制得脱甲基托品酮（1）; 1与Boc酸酐反应制得N-Boc-N-去甲托品酮（2）;以三仲丁基硼氢化锂为还原剂,2经还原反应立体选择性合成了内型N-Boc-N-去甲托品醇（内型/外型=6.5/1）,总收率60%,其结构经¹H NMR和ESI-MS确证。     

烯虫酯的立体选择性全合成

以香茅醛为起始原料, 通过羟醛缩合反应和Reformatskii反应得到3,7,11-三甲基-2,4,10-十二碳三烯酸异丙酯的双键顺反异构体混合物, 经苯硫酚两次催化双键顺反异构化, (2E,4E)-异构体3a的含量由原来的26%提高到85%. 再通过醚化反应, 立体选择性地全合成了具有保幼激素活性的昆虫生长调节剂烯虫酯及其异构体, 即11-甲氧基-3,7,11-三甲基-2,4-十二碳二烯酸异丙酯. 其中具有较高生物活性的(2E,4E)-异构体的含量达85%. 各步所合成的化合物的结构经IR, MS和NMR证实.