An Approach to Pancratistatins via Ring-Closing Metathesis:  Efficient Synthesis of Novel 1-Aryl-1-deoxyconduritols F

Abstract

Structurally novel cyclitols, 1-aryl-1-deoxyconduritols F, were efficiently prepared from d-xylose, utilizing RCM as a key step. Various aromatic residues were incorporated in the cyclitol skeleton with total stereochemical control, utilizing a diastereoselective aryl cuprate addition to a gamma-alkoxy enoate. The synthetic route establishes a firm foundation for a practical synthesis of the antitumor alkaloid pancratistatin and its aryl analogues. [structure: see text]

Glucocerebrosidase Enhancers for Selected Gaucher Disease Genotypes by Modification of α‐1‐C‐Substituted Imino‐D‐xylitols (DIXs) by Click Chemistry

“…Our approach was based on the protected advanced intermediate 3, [27] recently synthesized in one of our groups in five steps and 44 % overall yield from 2,3,4-tri-O-benzyl-d-xylopyranose (2) [28] (Scheme 2). Conversion of alkene 3 into the corresponding alkyne 4 was performed in two steps (68 % combined yield) by means of Lemieux-Johnson oxidative cleavage and reaction of the intermediate aldehyde with an excess of the Bestmann-Ohira reagent.…”

“…However, long alkyl chain derivatives may also be cytotoxic, mainly due to membrane insertion and pore formation. [34] To shorten the alkyl chain length while maintaining an optimal level of lipophilicity, a 3-trimethylsilylpropylgroup was introduced as a substituent by means of azide [28] (see Figure 2). Interestingly, the resulting iminoxylitol, DIX-28, showed an inhibitory potency similar to that of the above longer alkyl chain analogues.…”

Chapter 3 Chemical and Biological Aspects of Narcissus Alkaloids

“…A 2-arylcyclo hexanone was regio-and stereoselectively added to nitroethylene to access the octahydroindole core present in the alkaloids. Similarly, the addition of arylcuprates to enantiomerically pure conjugate esters derived from D-xylose, allowed, after pertinent FG transformations and ring-closing metathesis, the preparation of novel 1-aryl-1-deoxyconduritols F. These compounds are advanced intermediates en route to pancratistatin derivatives (283). Tomioka described a chemoselective conju gate addition -nitro Michael reaction sequence to prepare aand b-lycoranes in their racemic form (281).…”

A Facile Synthesis of Lentiginosine Analogues Based on a Highly Regio‐ and Diastereoselective Allylic Amination Using Chlorosulfonyl Isocyanate

“…[9] Wittig reaction of compound 8 with the DMSO anion in THF at 45°C afforded the olefin 9 as a 3.1:1 mixture of (Z)/(E) isomers in 94 % yield (Scheme 2). The hydroxy moiety of compound 9 was then converted into the bromide 7 with carbon tetrabromide, triphenylphosphane, and triethylamine in 89 % yield.…”