2,4-Diyn-l-ols

Mercuric sulfate/sulfuric acid 3(2H)-Furanones from l,3-diyn-5-ols... 

Photoinduced absorption studies of the oligomer have shown that the dominant long-lived photocarriers are bipolarons formed by interchain charge separation. The lifetimes of the bipolarons in poly(l-(A-carbazo-lyl)penta-5-acetoxy-l,3-diyn) are of the order of seconds at 80 K. The polymer of 1-(A-carbazolyl)-penta-l,3-diyne-5-ol, which is an intermediate compound in the synthesis of (61), has a very low band gap energy (1.6 eV) exhibits a strong non-linear optical... 

The diiodo derivative of dibenzo[a,e]cyclooctene (entry e, Table 24.25) undergoes cross-coupling with 2 equiv of 6-ferf-butyldiemthylsilyl-8-trimeth-ylsilyl-3-methyl-3-(Z)-octen-l,7-diyn-5-ol (ca. Scheme 24.30) to afford the silylalcohols as a 1 1 mixture of two diastereomers in 64% isolated yield. The subsequent KH treatment gives the corresponding Z,Z,Z,Z-tetraentetrayne (Scheme 24.34) [10]. 

Consequently,6-tert-butyldimethylsilyl-8-trimethylsilyl-3-methyl-3-(Z)-octe-ne-l,7-diyn-5-ol serves as a latent diendiyne moiety, which on cross-coupling with aryliodides provides an easy access to a variety of diendiynes, (Z,Z)-l-aryl-3,5-octadiene-l,7-diynes. These diendiynes are precursors of 5,6-diaryldibenzo[a,e] cyclooctenes. The generation of two diendiynyl moieties (tetraentetraynes) in the same molecule produces oligomers having multiple dibenzo[a,e]cyclooctenyl units. 

Di- and tetraynes with hydrogen sulfide in an alkaline medium at 20-80°C form systems containing linked thiophene cycles. Thus, l,4-dithienylbuta-l,3-diyne (47) forms 2,5-di(2-thienyl)thiophene (48) in 78% yield, whereas octa-2,4,6-tiiyn-l-ol (49) under the same conditions gives 5-hydroxymethyl-2-prop-1-ynylthiophene (50) in 50% yield (77HOU947). 

We have found these to be applicable in the desolvation of several organic inclusion compounds with volatile guests. There are examples of the other kinetic equations that describe clathrate decomposition. The decomposition of the inclusion compound l,4-di-(5//-dibenzo[a,rf] cycloheptene-5-ol)-buta-l,3-diyne with acetone, follows Prout-Tompkins kinetics ln(Q /(l — a)) = kt. 

Several nematicidal acetylenic compounds have been isolated. Most are from the Asteraceae (127). Recently isolated are (8R,9R, 10S)-9,10-epoxyheptadec-16-ene-4,6-diyne-8-ol and other compounds from Cirsium. iaponicum (128,129). 1-Phenylhepta-l,3,5-triyne and 2-phehyl-5-(1 -jjropynyl)-thiopene, from Coreopsis lanceolata and cis-dehydromatricaria ester from Soli dago altissima have been shown to be fly ovicidal substances (130,131). 

Various metal acetylides are used for smooth coupling with propargylic halides and acetates. 2,3-Alkadien-5-yn-l -ols are obtained by the reaction of 2-(l -alkynyl)oxiranes [28,29], As a synthetic application, the unstable 2,3-octadiene-5,7-diyn-l-ol (136), a fungus metabolite, has been synthesized by the coupling of 4-trimethylsilylbutadiy-nylzinc chloride (134) with 2-ethynyloxirane (135) followed by desilylation [31]. 

To a stirred solution of ( )-l-iodohept-l-yne 8 (222 mg, 1 mmol) and but-3-yn-l-ol 9 (140 mg, 2 mmol) in pyrrolidine (1.5 mL), under an argon atmosphere, was added Cul (19 mg, 0.1 mmol). After being stirred at room temperature for 30 min, the mixture was hydrolyzed with a saturated aqueous solution of NH4CI and extracted with diethyl ether. The organic extract was dried over MgS04, and the solvent was removed in vacuo. Filtration through silica gel (eluent petroleum ether/ethyl acetate, 6 4) gave 155 mg (95%) of pure 1,3-diyne 10. 

Scheme 11.46 Synthesis of 2,3-octadiene-5,7-diyn-l-ol 171 (fungus metabolite).

Pd-catalyzed allenylation-propargylation has hardly been applied to natural products synthesis. To date, the synthesis of ( )-2,3-octadiene-5,7-diyn-l-ol, a metabolite from fungus Cortinellus berkeleyams shown in Scheme 36, ° may well be the only example. 

Zn is the most versatile with respect to leaving groups and most satisfactory. This reaction has been applied to the synthesis of 2,3-octadiene-5,7-diyn-l-ol, a metabolite from the fungus Cortinellus berkeleyanus (Scheme 3.52) [174bj. To our knowledge, there does not appear to be any reported example of the Pd-catalyzed propargyl-alkynyl coupling. 

As propargylic alcohols can be isomerized to a, -unsaturated enones under Pd-catalyzed conditions,the isomerization reaction of l,4-diyn-3-ols shown in Scheme 5 likely proceeds via enynone intermediates, as shown in Scheme 6. In view of the same transformation catalyzed by PPhs without Pd, ° it is very desirable to firmly establish the necessity for Pd. 

To study the effect of the cinnoline heterocycle on the reactivity of 10-membered enediynes, the rates of Bergman cyclization of compound 3.824 and 3,4-benzocyclodeca-l,5-diyne-7-ol 3.827 were compared at 75°C in 2-propanol. The products were analyzed by high-performance liquid chromatography (HPLC). The reaction obeys first-order kinetics and enediyne 3.824 is four orders of magnitude more active than benzo-fused analog 3.827 [381a]. 

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