D-glucose-derived aldehyde

However, this multistep procedure is experimentally complex. A simpler variation described in 199127 consists of the reaction of an aldehyde and a nitro compound in the presence of triethylamine, TBAF and tert-butyl-dimethylsilyl chloride. Under these conditions, nitro sugars are obtained in good yieds and higher diastereoselectivities than those afforded by the standard conditions. This procedure was used in several synthesis of 2-nitro-2-deoxyaldoses, as for the condensation of l,l-diethoxy-2-nitroethane and l,2 3,4-di-0-isopropylidene-a-D-galacto-hexodialdo-l,5-piranose.28 More recently, it was applied to the addition of ethyl nitroacetate to the D-glucose derived aldehyde 18, to give nitro sugar derivatives 26, key precursors of polysubstituted cyclohexane a-amino acids (Scheme 10).29... 

Fig. 16 Cycloaddition reaction of 0-allyl derivative of D-glucose derives aldehyde with aniline...

The total synthesis of (+)-cyclophellitol containing a fully oxygenated cyclohexane ring was accomplished by T. Ishikawa and co-workers. The synthetic strategy was based on the intramolecular silyl nitronate [3+2] cycloaddition reaction. The cycloaddition precursor was prepared by the Henry reaction starting from a D-glucose-derived aldehyde. 

Introduction of the more bulky carbohydrate moiety increases the shielding on one of the faces of the formyl group. The D-galactose derived aldehyde 10 adds to 1-methoxy-l.3-butadiene (1) with complete diastereoselectivity. D-Ribose and D-glucose derived aldehydes 13 and 14 are less efficient, but the cycloadducts 15 and 17 are still produced with high diastereomeric ratios22. 

Sabitha et al. published an analogous reaction utilizing a D-glucose-derived aldehyde 337 for the construction of the Yonemitsu reaction product 338 (Scheme 13.75) [128]. The aldehyde 340 containing a free hydroxyl group directly led to a decarboxylative cyclization step with the Meldrum s acid moiety, subsequent to the formation of the Yonemitsu product providing 7-(l//-3-indolyl)-2,3-dimethoxy-perhydrofuro[3,2-b]pyran-5-ones 341 in good yields (74-84%). 

In the case of the above mentioned benzoyl-D-glucose derivatives a correlation was found between the formation of D-glucose dibenzamide and the permanent or transitory existence of a free aldehyde group. The same behavior was noted for triacetyl-oZdehydc-L-erythrose (XLI), which by the action of ammonia produces L-erjrthrose diacetamide (XLII). Isbell and Frush have obtained a similar result in the case of tetraacetyl-oWe/it/do-L-arabinose which, when treated with methanolic ammonia, gave L-arabinose diacetamide in 53 % yield. 

In a variation of this method, Garcia Ruano and workers prepared 5-alkyl sulfinimines from the diacetone-D-glucose derived sulfinate 50.38 Subsequent treatment with LiHMDS, aldehyde, and CsF afforded S-te/t-butyl sulfinimines 51 in enantiomerically pure form.38... 

Another promising asymmetric allylation of aldehydes, mediated by a D-glucose-derived titanium reagent (54), has recently been described... 

An important development is the use of D-glucose-derived alkoxy ligands on titanium in cyciopentadi-enyldi(alkoxy)titanium enolates, which undergo efficient enantioselective aldol reactions with aldehydes. The chiral titanium reagent (30), prepared from reaction of cyclopentadienyltitanium trichloride with two equivalents of (l,2 5,6)-di-0-isopropylidene-a-D-glucofuranose, can be used to transmetal late the lithium enolate of t-butyl acetate in ether solution (equation 10). The titanium enolate generated is then... 

The D-glucose derivative (49) serves as a convenient source for preparing both enantiomers of the precursor (50) for the antitumour compound sesbanimide. Scheme 11 outlines the synthesis of the D-enantiomer the L-form was obtained by demasking the aldehyde at... 

Scheme 7.7 Alkylations of aromatic aldehydes with AlR and (AlR 3)2-DABCO in the presence of an in situ generated nickel catalyst from a D-glucose-derived phosphoramidite ligand.

An effective synthesis of N-(1-deoxy-D-fructos-l-y1)amino acids, e.g., the product (38) that would be produced in the Maillard reaction of L-vallne with D-glucose, involved reductive aminatlon with the D-fructose derived aldehyde (39) (Scheme 9). Methyl... 

Jl exists in this form only in solution, though stable derivatives of the aldehyde structure are known. The optical antipode of D-glucose in which the positions of every H and OH are transposed is L-glucose. 

In another approach, a glucose-derived titanium enolate is used in order to accomplish stereoselective aldol additions. Again the chiral information lies in the metallic portion of the enolate. Thus, the lithiated /m-butyl acetate is transmetalated with chloro(cyclopentadienyl)bis(l,2 5,6-di-0-isopropylidene- -D-glucofuranos-3-0-yl)titanium (see Section I.3.4.2.2.I. and 1.3.4.2.2.2.). The titanium enolate 5 is reacted in situ with aldehydes to provide, after hydrolysis, /i-hydroxy-carboxylic acids with 90 95% ee and the chiral auxiliary reagent can be recovered76. 

Table 6. (7 )-a-Hydroxyalkanones Derived from Various Aldehydes D- glucose... 

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