6617-37-4

Upstream product

• 193478-02-3 (2Z,6E)-9-Furan-3-yl-2,6-dimethyl-nona-2,6-diene-4,8-diyn-1-ol 
• 193478-00-1 (E)-5-Furan-3-yl-2-methyl-pent-2-en-4-ynoic acid methyl ester 
• 193478-01-2 (E)-6-(3-furanyl)-3-methyl-3-hexene-1,5-diyne 
• 147675-99-8 3-(2,2-dibromovinyl)furan 
• 193478-07-8 (3E)-1,1-dibromo-6-(3-furanyl)-3-methyl-1,3-hexadien-5-yne 
• 53768-17-5 (E)-5-(3-furanyl)-2-methyl-2-penten-4-ynal 
• 53768-06-2 (E)-5-(3-furanyl)-2-methyl-1-[(tetrahydropyranyl)oxy]-2-penten-4-yne 
• 53768-16-4 (E)-5-(3-furanyl)-2-methyl-2-penten-4-yn-1-ol 
• 53768-03-9 (E)-2-methyl-1-[(tetrahydro-2H-pyran-2-yl)oxy]-2-penten-4-yne 
• 51061-85-9 3-ethynylfuran 
• 616-02-4 citraconic acid anhydride 
• 22122-36-7 3-methyl-5H-furan-2-one 
• 61550-03-6 2-trimethylsilyloxy-3-methylfurane 
• 498-60-2 furan-3-carboxaldehyde 

Downstream Products

• 104049-40-3 2-methyl-3-<2'-(furan-3-yl)-3'-hydroxy-5'-methylphenyl>propenoic acid 

Relevant academic research and scientific papers

Pd-catalyzed stereocontrolled synthesis of γ-alkylidenebutenolide, freelingyne

A stereocontrolled synthesis of freelingyne was established by Pd(0)catalyzed coupling of vinyl halides with acetylene derivatives, followed by Pd(II)-catalyzed intramolecular stereoselective γ-(Z)-alkylidenebutenolide formation.

Stereoselective synthesis of freelingyne and related γ-alkylidenebutenolides via vinylogous Mukaiyama aldol additions

Following the strategy of Scheme 1, a Mukaiyama aldol addition/anti-elimination route to stereopure γ-alkylidenebutenolides 4 was established. The addition giving 27 was only moderately diastereoselective but the products lk- and ul-27 were chromatographically separable (Scheme 4). They underwent highly selective anti-eliminations in the presence of triflic anhydride-pyridine or Burgess' reagent, furnishing the thiophene-containing butenolides Z- and E-28, respectively (Scheme 5). The Mukaiyama aldol addition leading to compound 29 was 100% lk-selective when mediated by BF3 etherate and 87 : 13 ul-selective in the presence of ZnBr2 (Scheme 6). Stephens-Castro couplings of the resulting butenolides lk- and ul-29 with 3-ethynylfuran proceeded with complete conservation of the stereochemical integrity (Scheme 7). The subsequent anti-eliminations of water were best realized by treatment with DEAD-PPh3. They provided freelingyne (Z-9) with ds = 92 : 8 and its isomer E-9 with ds = 98 : 2 (Scheme 8). Analogously, the differently substituted (trimethylsiloxy)furans 15 or 16 provided the freelingyne analogs Z-10, E-10 and Z-11 (Schemes 6-8).

Z-ore E-configurated γ-alkylidenebutenolides from a 2- (trimethylsiloxy)furan and iodomethacrolein - Stereoselective synthesis of Z- and E-freelingyne

The γ-(α-hydroxylalkyl)butenolides lk-5 and ul-5 were prepared by Mukaiyama aldol additions between iodoaldehyde 10 and the trimethylsiloxy-substituted furan 6 in the presence of BF3·OEt2 and ZnBr2, respectively. Couplings of these butenolides with 3- ethynylfuran followed by anti-eliminations of water mediated by DEAD/PPh3 led to Z-freelingyne (Z-11 dy = 92:8) anti E-freelingyne (E-11: ds = 98:2).