176041-42-2

Upstream product

• 22122-36-7 3-methyl-5H-furan-2-one 
• 80522-42-5 triisopropylsilyl trifluoromethanesulfonate 

Downstream Products

• 22122-36-7 3-methyl-5H-furan-2-one 
• 1089205-89-9 C₂₁H₃₁BrO₄Si 
• 1203511-19-6 C₂₁H₃₁BrO₄Si 
• 173792-58-0 gymnodimine A 

Relevant academic research and scientific papers

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.

Vinylogous Mannich reactions. The asymmetric total synthesis of (+)-croomine

We have recently investigated the vinylogous Mannich reaction as a key construction for the synthesis of alkaloid natural products. The general plan is illustrated by the nucleophilic addition of 2-trialkylsilyloxy furan to the cyclic iminium ion to provide a mixture of the isomeric adducts threo-5 and erythro-5 in which the threo-5 product typically dominates. Since the stereochemistry at the newly created stereogenic centers in the threo-5 adduct corresponds to the pairwise relationships at C(9)-C(9a) and C(3)-C(14) of croomine (1), it occurred to us that vinylogous Mannich reactions might be applied to the design of a highly convergent strategy for the synthesis of 1 and related alkaloids. We report the successful implementation of this strategy in an extraordinarily concise, asymmetric synthesis of (+)-croomine (1).

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.

Diastereoselective addition of nitro compounds to α,β- unsaturated γ-butyrolactones

Herein, we report our results on the diastereoselective addition of nitro compounds to α,β-unsaturated γ-butyrolactones, which afforded the corresponding Michael adducts 9-17 in moderate to good yields and good to excellent diastereoisomeric ratio. A one-pot conversion of α,β- unsaturated γ-butyrolactones 7 and 8 to the corresponding trisubstituted keto-γ-butyrolactones 24 and 25 via a tandem Michael-Nef protocol is also described.

Synthetic study on Pandanus Alkaloids: from Norpandamarilactonines to Pandamarilactonines, a Proof of their Configurational Instability

The ethyl carbamate of norpandamarilactonine-A was prepared in an enantiomerically pure form starting from (S)-prolinol. Deprotection of the amine functionality rendered both diastereomeric norpandamarilactonines as racemates, which were used as synthetic precursors of pandamarilolactonine-A and -B.

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.