Stereocontrolled synthesis of chiral

Ikota, N., O. Yoshino, and K. Koga Synthetic Studies on Optically Active p-Lactams. Stereocontrolled Synthesis of Chiral Thienamycin Intermediates from D-Glucose. Chem. Pharm. Bull. 30, 1929 (1982). 

Shiozaki, M., N. Ishida, T. Hiraoka, and H. Yanagisawa Stereocontrolled Synthesis of Chiral Intermediates of Thienamycin from Threonines. Tetrahedron Letters 22,5205 (1981). 

The use of Et2Zn additions for the stereocontrolled synthesis of chiral secondary alcohols is extensive. In an early application, Evans demonstrated the utility of the method for one of the more complicated substrates that has... 

The necessity for producing large amounts of synthetic prostaglandins and analogs provided the impetus for a number of improvements in the bicyclo[2.2.1]heptene approach. Especially important was the development of an enantioselective modification for the synthesis of chiral prostanoids without resolution (1975) and the invention of a chiral catalyst for the stereocontrolled conversion of 15-keto prostanoids to either 15(5)- or 15(7 )- alcohols. 

Guga P, Okruszek A, Stec WJ (2002) Recent Advances in Stereocontrolled Synthesis of P-Chiral Analogues of Biophosphates. 220 169-200... 

The stereocontrolled synthesis of a chiral, polyhydroxy 1,7-dioxa-spiro[5.5]undecene from 2,3,4,6-tetra-O-benzyl-D-glucono-1,5-lactone... 

Recent Advances in Stereocontrolled Synthesis of P-Chiral Analogues of Biophosphates... 

A related approach was recently successful for the stereocontrolled synthesis of an antibiotic. In this synthesis the Japanese chemists used (S)-3-[(benzyloxycarbonyl)-amino]-4-(methoxycarbonyl)butyric acid as chiral auxiliary186). 

Guga P, Okruszek A, Stec WJ (2002) Recent Advances in Stereocontrolled Synthesis of P-Chiral Analogues of Biophosphates. 220 169-200 Hackmann-Schlichter N, see Krause W (2000) 210 261-308 Hadjiaraoglou LP, see de Meijere A (2000) 207 149-227... 

In recent years, most of the attention has focused on the stereocontrolled synthesis of cyclopropanes. The isolation of several structurally intriguing natural product has revived the interest of the scientific community for the development of new methods. Several efficient and practical chiral auxiliaries have been developed for the enantioselective cyclopropanation of olefins. The most efficient chiral auxiliaries have been specifically designed for the cyclopropanation of acyclic allylic alcohols (Table 13.3, entry 1, 2, Protocol 8),24 alkenones,25 cycloalkenones26 (Table 13.3, entry 3,4, Protocol 9), vinyl ethers27 (Table 13.3, entry 5, Protocol 10), and vinylboronate esters28 (Table 13.3,... 

A stereocontrolled synthesis of the biologically active neolignan (+)-dehydrodiconiferyl alcohol, which was isolated from several Taxus species, was achieved via Evans asymmetric aldol condensation [58] using ferulic acid amide derived from D-phenylalanine. The reaction steps are shown in Fig. 9. This stereocontrolled reaction is also useful for preparing the enantiomer of (+)-dehydroconiferyl alcohol using chiral auxiliary oxazolidinone prepared from L-phenylalanine. This reaction also enables the syntheses of other natural products that possess the same phenylcoumaran framework. 

The 5,8-disubstituted indolizidines and 1,4-disubstituted quinolizidines are the more common structural patterns found in amphibian skin[21]. None of these alkaloids has so far been reported from any other source. In addition, the biological activity of only a few 5,8-disubstituted indolizidines has been investigated due to the isolation in minute quantities from the skin. Among them, the relative stereochemistry of quinolizidine 2071 was anticipated to be 75 by our chiral synthesis of 76[35] followed by stereocontrolled synthesis of 75[36]. A sample of synthetic racemate of 75 had produced the best separations on GC analysis with (3-dextrin chiral column[36]. 

The methods for stereocontrolled synthesis of cyclopropylboronic esters have been studied (Scheme 29). The palladium-catalyzed reaction of diazoalkanes (method A), Simmons-Smith reaction (method B), or asymmetric Simmons-Smith reaction using chiral diamines such as 270 (method C) for chiral or achiral 1-alkenylboronic esters... 

An ingenious stereocontrolled synthesis of pentalenolactone (300) has been recorded by Danishefsky et in which three of the five chiral centres are incorporated into a key tetracyclic intermediate (Scheme 45). Two other... 

Guijar, M K, Kumar, P, Rao, B V, Stereocontrolled synthesis of spirocyclopropane sugars and their application to asymmetric formation of tertiary chiral centres a route to 2,2 -diaIkylated pyranose subunit (C-18-C-23) of lasonolide A, Tetrahedron Lett., il, 8617-8620, 1996. 

---