Other oxygen heterocycles

Di-O-isopropylidene-D-glucose can be converted into 85 by known procedures, and this has been used to prepare the lactone 86, thus providing a new formal synthesis of (-)-7rans-kumausyne (87). In a synthetic approach to the 

A tetrahydrofuran ring has been annelated onto a sugar by means of the radical cyclization of 102 which gave 103 on treatment with triphenylstannane and triethylborane.  

When the diazospecies 109, prepared by diazo transfer fron mesyl azide, was treated with Rh2(OAc)4 in benzene under reflux, the two products 110 and 111 were formed in a ratio of 38 62. Use of the corresponding Pmb ether gave only 

Reaction of the alkenyl carbene complex 117, derived from tetra-O-benzyl-aldehydo-D-hbose, with cyclohexene oxide in the presence of [Cp2TiCl]2 gave the oxa-trans-decalin complex 118, together with a smaller proportion of the epimer at the asterisked carbon. This work was extended to the use of sugar epoxide 119 and the carbene complex 120 to give the dioxabicyclo-system 121.  

Reagents i, dimethyldioxirane ii, CH2=CH-CH2MgCI iii, O3, then PhsP iv, MeOCH=PPh3  

Both the naturally occurring (7R, 8S) isomer of the gypsy moth pheromone disparlure (31) (sugar chain numbering) and its enantiomer 

The relative stereochemistry of the fungal toxins AK-I and -II was established by the synthesis of the pair of epoxides (32) from L- 

Full details have been reported of the synthesis of pseudomonic 

Goldinonolactone (40) and the chiral tetrahydrofuran (41) were key intermediates in a chiral, but non-carbohydrate-based, synthesis of the antibiotic aurodox both these intermediates are also accessible from carbohydrates, (40) being made from an L—mannose derivative and (41) from D-mannose via a previously described acetyl- 

D-xylose and D-mannose, and then.linked it with (43), made from fructose, to give, after free-radical decarboxylation, the trimeric unit (44).  

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In general, the synthetic routes described provide adequate and convenient routes to chromones, such that their synthesis from other oxygen heterocyclic compounds is not of significant value. The following examples are therefore better considered as reactions of the heterocycle and are dealt with in more detail in the appropriate sections of Chapter 2.23. 

J. W., Mass Spectral Techniques in Heterocyclic Chemistry Applications and Stereochemical Considerations in Carbohydrates and Other Oxygen Heterocycles, 42, 335. 

Carbohydrates and other oxygen heterocycles, applications of mass spectral techniques and stereochemical considerations in, 42, 335 Carbolines, 3, 79... 

Mass spectral techniques in heterocyclic chemistry applications and stereochemical considerations in carbohydrates and other oxygen heterocycles, 42, 335 Mass spectrometry of heterocyclic compunds, 7, 301 of nucleic acids, 39, 79 Medium-large and large 7r-excessive heteroannulenes, 23, 55 Meso-ionic compounds, 19, 1 Metal catalysts, action on pyridines, 2, 179 Metalation, directed, of pyridines, quinolines, and diazines, 52, 187... 

Applications and Stereochemical Considerations in Carbohydrates and Other Oxygen Heterocycles ... 

The final chapter is concerned with the application of mass spectral techniques in heterocyclic chemistry, in particular to carbohydrates and other oxygen heterocycles, and is authored by J. R. Jocelyn Pare, K. Jankowski, and J. W. ApSimon. 

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