Synthesis and chemistry of cyclopropanated carbohydrates

Abstract

This review provides a synopsis of the formation and chemistry of cyclopropanated carbohydrates. The organization begins with methods for the formation of the cyclopropanated carbohydrate followed by the chemistry of the bicyclic system. Examples of new reactions and rearrangements leading to new products and the synthesis of natural products are presented.

Remarkable Oxidation Stability of Glycals: Excellent Substrates for Cerium(IV)-Mediated Radical Reactions

“…Indeed, even a remote effect of para-substituents of the benzoate groups on the reaction time was established (entries [12][13][14], and again, the unprotected 3-position afforded some oxidative byproduct (entry 11).…”

“…11 This reaction is similar to Lemieux's azidonitration, 12 but provides easy access to C-2-branched carbohydrates, a valuable complement to the cyclopropanation of glycals. 13 More recently, we applied this methodology to other CH acidic radical precursors (e.g., nitromethane or nitro esters) 14 and to unsaturated carbohydrates with benzyl protecting groups. 15 In all cases, the double bond of glycals 1 was not directly affected by CAN, although this reagent has an oxidation power (E 1/2 ox ) 1.52-1.60 V vs NHE) 16 sufficient to oxidize unsubstituted 2,3-dihydropyran (E pa ) 1.60 V vs NHE).…”

Vinyl Sulfone Modified Hex‐3‐enopyranosides: Novel Routes to C3–C4 and C4–C5 Cyclopropanated Pyranosides

“…[1] This particular combination offers a class of strained and reactive cyclopropanes embedded in chiral appendages. Development of strategies for the synthesis of this class of compounds is important, because in general, chemists have long been fascinated by the presence of cyclopropane subunits in a wide range of natural products and the usefulness of this strained cycloalkane in synthetic chemistry.…”

“…Development of strategies for the synthesis of this class of compounds is important, because in general, chemists have long been fascinated by the presence of cyclopropane subunits in a wide range of natural products and the usefulness of this strained cycloalkane in synthetic chemistry. [2] Moreover, barring a few reports, the large number of metal-mediated synthetic routes to cyclopropane-fused furanosyl [1][2][3] and pyranosyl [2,4] carbohydrates are based on the ritualistic use of glycals as starting materials. Although glycals are suitable intermediates for the synthesis of C1-C2 and C4-C5 cyclopropanated pyranosides, there is virtually no method available till today for the synthesis of C3-C4 cyclopropanated pyranosides.…”

Asymmetric one-pot synthesis of cyclopropanes

“…Additionally, naturally occurring macrolides often contain branched polyol sequences, a structural motif that portends an origin from a C-branched sugar [14]. One of the most important advances in cyclopropane chemistry over the last decade has been the integration of cyclopropanes and carbohydrates [15]. Carbohydrates have an exciting history in organic and medicinal chemistry [16].…”