203131-19-5

Upstream product

• 6124-79-4 4-methyl-2(5H)-furanone 
• 80522-42-5 triisopropylsilyl trifluoromethanesulfonate 
• 616-02-4 citraconic acid anhydride 

Downstream Products

• 21053-63-4 methyl-3 phenyl-4 Δ²⁽³⁾-butyrolactone 
• 40834-42-2 5-hydroxy-4-methyl-5H-furan-2-one 
• 39007-93-7 sesquirosefuran 

Relevant academic research and scientific papers

Biomimetic total synthesis of litseaverticillols B, E, I, and J and structural reassignment of litseaverticillol E

Equation presented. The first total synthesis of litseaverticillols B (1), E (2), I (4), and J (5) as well as the structural reassignment of litseaverticillol E (2) have been achieved by means of a biomimetic sequence of transformations during which a [4 + 2]-initiated reaction cascade and an ene reaction, both involving singlet oxygen (1O2), formed key steps. The reassignment of the structure of litseaverticillol E (3) to include an allylic hydroperoxide provides strong support for our biogenetic hypothesis.

Biomimetic Total Synthesis of Litseaverticillols A, C, D, F, and G: Singlet-Oxygen-Initiated Cascades

Natural weapons against HIV, litseaverticillols A (2) and C, have been synthesized from sesquirosefuran (1) by a rapid and efficient biomimetic total synthesis involving a chemo- and stereoselective singlet-oxygen-initiated tandem sequence (see scheme). Litseaverticillols D, F, and G were readily synthesized from litseaverticillol A through a regioselective 1O 2 ene reaction.

Illustrating the power of singlet oxygen chemistry in a synthetic context: Biomimetic syntheses of litseaverticillols A-G, I and J and the structural reassignment of litseaverticillol E

Biomimetic syntheses of the litseaverticillols A-G, I and J are reported herein. The syntheses rely heavily on the application of two different modes of reaction for photochemically generated singlet oxygen, namely, the [4+2] cycloaddition of singlet oxygen (1O2) with furans and the ene reaction of 1O2 with double bonds. The highlight of these syntheses is a one-pot cascade sequence, involving five synthetic operations initiated by a [4+2] reaction, to form the fully functionalised litseaverticillol core. A series of regioselective ene reactions are then used to appositely functionalise the side chains. The synthesis of litseaverticillol E (both its originally proposed and its actual structures) allows a structural reassignment of this natural product.

Comparative studies of palladium and copper-catalysed γ-arylation of silyloxy furans with diaryliodonium salts

The γ-arylation of substituted silyl-activated butenolides has been studied using a broad scope of unsymmetrical hypervalent diaryliodonium salts via a palladium- or copper-catalysed coupling reaction, yielding interesting reactivity trends. The mild catalytic conditions and coupling partner variability provide access to synthetically useful building blocks toward the pursuit of aryl-lactone containing natural products and allows for facile diversification.

Synthesis of Penta-2,4-dien-1-imines and 1,2-Dihydropyridines by Rhodium-Catalyzed Reaction of N-Sulfonyl-1,2,3-triazoles with 2-(Siloxy)furans

A rhodium(II)-catalyzed reaction of N-sulfonyl-1,2,3-triazoles with 2-(siloxy)furans is reported. Either open-chain penta-2,4-dien-1-imines or cyclic 1,2-dihydropyridines are selectively obtained depending on the ligand on rhodium(II).

Cyclopropanation of (E)-Dehydroaspartic Acid Esters with Furan Derivatives: The Synthesis of Highly Functionalized α-2,3-Methanoamino Acid Esters

Highly functionalized α-2,3-methanoamino acid esters were prepared by the cyclopropanation of dehydroaspartic acid esters with 2-methoxyfuran or 2-siloxyfuran derivatives. These reactions proceed smoothly in the absence of any catalysts, bases, additives, or solvents.

Applications of vinylogous mannich reactions. Concise enantiospecific total syntheses of (+)-croomine

Because the vinylogous Mannich reaction of substituted furans with iminium ions is a useful construction in alkaloid synthesis, it is important to know what effects substituents on the two reacting partners have upon the stereoselectivity of the reaction. Toward this end, the additions of the methylated furans 9a-h to the iminium ion generated in situ from the ethoxy carbamate 10 were examined. Generally, mixtures (3-24:1) of the threo and erythro adducts 11a-h and 12a-h were obtained in 50-96% combined yields, with the threo isomers being the major products. Two extraordinarily concise asymmetric syntheses of (+)-croomine (1) have been completed using a novel strategy, highlighted by two vinylogous Mannich reactions as key constructions. The first such reaction involved the addition of 5-(4-bromobut-1-yl)-3-methyl-2-(triisopropylsilyloxy)furan to the N-acyliminium salt derived from the L-pyroglutamic acid derivative 17 to give the adduct [5(S),2′(S),5′(S)]-5-(4″-bromobut-1″yl)-5-[N-(tert- butoxycarbonyl)-2′-(methoxycarbonyl)-pyrrolidin-5′-yl]-3-methyl- 2(5H)-furanone (18) as the major product. Refunctionalization of 18 led to the tricyclic intermediate [3′S-[3′α,9′α(5*),9′aα]]- decahydro-4-methyl-5-oxospiro[furan-2(3H),9′-[9H]pyrrolo[1,2-a]azepin]- 3′-carboxylic acid, hydrobromide salt, which was, in turn, converted to an iminium salt that underwent a second vinylogous Mannich reaction to give [3′S-[3′α(R*),9′α(S*), 9′aα]]-3′-(2,5-dihydro-4-methyl-5-oxo-2-furanyl)decahydro-4- methylspiro[furan-2(5H),9′-[9H]pyrrolo[1,2-a]azepin-5-one (24) as the major adduct. Stereoselective reduction of the unsaturated lactone 24 gave 1, completing a synthesis that required a total of only 11 chemical steps from commercially available starting materials. In a second approach, the initial Mannich adduct [5(S),2′(S),5′(S)]-5-(4″-bromobut-1″-yl)-5-[2′- (methoxycarbonyl)pyrrolidin-5′-yl]-3-methyl-2(5H)-furanone was transformed into the unsaturated tricyclic intermediate [3′S-[3′α(R*),9′α(S*), 9′aα]]-3′-(2,5-dihydro-4-methyl-5-oxo-2-furanyl)-1′, 2′,3′,5′,6′,7′,8′-octahydro-4- methylspiro[furan-2(5H),9′-[9H]-pyrrolo[1,2-a]azepin]-5-one, which underwent hydrogenation to give 1 as the only isolable product, thereby completing a synthesis that required only 10 steps.