From carbohydrate precursor

In plants phenol biosynthesis proceeds by building the aromatic ring from carbohydrate precursors that already contain the required hydroxyl group... 

Phenol biosynthesis in plants proceeds from carbohydrate precursors whereas the pathway in animals involves oxidation of aromatic rings... 

Structural drawings of carbohydrates of this type are called Haworth formulas, after the British chemist Sir Walter Norman Haworth (St Andrew s University and the University of Birmingham) Early m his career Haworth contributed to the discovery that carbohydrates exist as cyclic hemiacetals rather than m open chain forms Later he col laborated on an efficient synthesis of vitamin C from carbohydrate precursors This was the first chemical synthesis of a vitamin and provided an inexpensive route to its prepa ration on a commercial scale Haworth was a corecipient of the Nobel Prize for chem istry m 1937... 

Trihydroxyazepanes (trideoxy-l,6-iminohexitols) have also been prepared from carbohydrate precursors and activities as inhibitors of selected glycosidase enzymes assessed... 

Liebeskind and coworkers have examined the reactivity of (2//-pyran)Mo(CO)2Cp+ cations 210, which may be prepared in optically active form from carbohydrate precursors. Nucleophilic attack on cation 210 occurs at the diene terminus bonded to the ring oxygen to give jr-allyl complexes 51 (Scheme 53)85. Hydride abstraction from 51 gives the cation 54 addition of a second nucleophilie occurs regioselectively to give... 

Toward a screening program for RhuA stereoselectivity, structurally more simplified dioxane derivatives 25-27 comprising enantiomeric and diastereomeric 3-hydroxyaldehyde geometries in a conformationally defined environment could be prepared easily from carbohydrate precursors (Scheme 2.2.5.10). First results from product analysis provide further evidence for occasionally biased fixation of... 

Convergent construction directed toward the preparation of enantiomerically-pure targets depends on the availability of enantomerically-pure starting materials. There are many ways that these can be prepared. One way is from carbohydrate precursors, but this approach has been limited, in that L-sugars are much more expensive than D-sugars. Tzenge-Lien Shih of Tamkang University in Taipei describes (Tetrahedron Lett. 45 1789, 2004) the facile conversion of the inexpensive D-ribonolactone derivative 1 to the much more valuable L-ribonolactone derivative 3, by careful hydrolysis of the intermediate mesylate. The epoxide 2 is presumed to be an intermediate in this transformation. 

Kevin J. Quinn of the College of the Holy Cross chose (Organic Lett. 2005, 7, 1243) a complementary approach in his synthesis of rollicosin. The symmetrical diol 4 is also available from carbohydrate precursors. Monosilylation followed by esterification with acryloyl chloride gave 5. Exposure of 5 to the Grubbs catalyst in the presence of 6 led, by ring-closing metathesis and cross metathesis, to the y-lactonc 7. Note that 5-lactone formation did not compete ... 

Enyne metathesis can also be used with highly substituted substrates. Catherine Lievre of the Univcrsite de Picardie reports (J. Org. Chem. 2004,69, 3400) that enynes such as 11, readily prepared from carbohydrate precursors, are cyclized by the second generation Grubbs catalyst 2 to the enantiomerically-pure cyclic dienes, exemplified by 12. 

R. E. Ireland and J. P. Vevert, A chiral total synthesis of (—) and (+) nonactic acids from carbohydrate precursors and the definition of the transition for the enolate Claisen rearrangement in heterocyclic systems, J. Org. Chem. 45 4259 (1980). 

Typically a hept-6-enyI radical will cyclize much slower than the corresponding hex-5-enyl radical, and often significant proportion of the primary radical is trapped before cyclization, and the olefinic product results. However, with the appropriate substituents or an activated acceptor, hepenyl radical cyclization can be used to prepare 6-membered carbocycles from carbohydrate precursors. For example, Redlich et al. [35] reported that 1,2-dideoxyhept-l-enitol derivatives can be cyclized to carbahexose derivatives [Eq. (II)]. Even though structural requirements (protecting groups, configuration of atoms in the carbon chain, and... 

The sixth theme, catbocycks from carbohydrates, explores bow functionalized cy-lopentanes and cyclohexanes can be prepared from carbohydrate precursors, thereby attending the usefulness of sugars for the synthesis of mainstream organic compounds. 

A. F. Sviridov, A. Yu. Romanovich, and O. S. Chizhov, Synthetic studies in polyene macrolide antibiotics. 1. Synthesis of C1-C6 and C7-C12 fragments of amphothericin-B from carbohydrate precursors, Bioorg. Khim., (1987) 1665-1671. 

Quite recently, Marco-Contelles [73] has made use of free radical cyclization and ring-closing metathesis in order to develop useful synthetic protocols to access a number of chiral non-racemic, densely oxygenated medium-sized carbocycles from carbohydrate precursors. 

Synthesis of /3-lactams from carbohydrate precursors 92WCH821. 

The review will be limited to atom- and bond-bridged bicyclic monomers. The important work of Bailey on the polymerization of spiro bicyclo orthoesters and spiro bicyclic orthocarbonates has been adequately described elsewhere 0 1 60 3. The outstanding and systematic body of work by Schu-erch2 3> and others on the ring opening polymerization of bicyclic acetals derived from carbohydrate precursors will also not be covered here. 

Hanessian, S, Synthesis of hydropiperidines from carbohydrate precursors, Chem. Ind. (Land.), 51, 2126-2127, 1966. 

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