L»Decyne

The BF3-induced reactions of iodosylbenzene with l-trimethylsilyl-3-aryl-l-propynes in dioxane follow a divergent course and afford aryl silylethynyl ketones (equation 28)31. The ketone derived from l-trimethylsilyl-3-phenyl-l-propyne is also generated in dichloro-methane, but as a minor product. These oxidations are apparently facilitated by the presence of benzylic hydrogen atoms, since a similar alkynyl ketone is not obtained from 1-trimethylsilyl-l-decyne with PhIO/BF3 in dioxane31. 

The production of 1-chloro-l-decyne and 1 -chloro-3- -pentylcyclopentene from the former iodonium compound and 1-bromo-l-decyne from the latter cannot be accounted for by the a-elimination mechanism. 

How would you synthesize stearolic acid (Problem 27.19) from 1-decyne and l-chIoro-7-iodoheptane ... 

Tetramethyl-5-decyne-4,7-diol, l 249t effective surfactant for coatings, 7 124... 

The boronic acid ester B was synthesized by transesterification of the corresponding pinacolester A with (lR,2R)-l,2-dicyclohexyl-l,2-dihydroxyethane. Stereoselective chlorination of B was carried out with (dichloromethyl) lithium and zinc chloride. Reaction of the obtained chloroboronic ester C with lithio 1-decyne followed by oxidation of the intermediate D with alkaline hydrogen peroxide afforded the propargylic alcohol E. Treatment with acid to saponify the tert-butyl ester moiety and to achieve ring closure, produced lactone F. Finally, Lindlar-hydrogenation provided japonilure 70 in an excellent yield and high enantiomeric purity. 

A. (E)-l-Deaenyidiisobutylalane. An oven-dried, 300-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, a rubber septum inlet, and an outlet connected to a mercury bubbler is flushed with nitrogen, immersed in a water bath kept at room temperature, and charged with 22.6 ml (125 mmol) of 1-decyne (Note 1) and 80 mL of hexane (Note 2). To this flask is added dropwise, with stirring, 22,3 mL (125 mmol) of diisobutylaluminum... 

Decyn-l-ol (Farchan Labs., Lancaster Synthesis) was used without further purification. Upon addition of 2-decyn-l-ol to the reaction mixture slight warming is observed. The temperature is maintained at 25-30°C using a water bath. 

It is not satisfactory to employ 1,2-diaminoethane in place of 1,3-diaminopropane. The reagent is not as stable addition of potassium tert-butoxide results in the immediate formation of a deep purple solution. Isomerizations proceed to completion, but yields are somewhat reduced (by about lOX in the case of the rearrangement of 2- to 9-decyn-l-ol). 

Reaction of l-bromo-2-butyne with hexylmagnesium bromide to give a mixture containing equal amounts of 1-methyl-1-hexylallene and 2-decyne... 

The metabolism of oleftnic or acetylenic substances to electrophilic metabolites is greatly reduced when the oleftnic or acetylenic moieties are not terminal, or are terminal but contain alkyl substituents on the allylic and propargylic positions. 1-Heptene, for example, is bioactivated to electrophilic metabolites whereas 3-hexene, 2-methyl-l-hepteneand3,3-dimethyl-l-hexenearenot [36,37]. Similarly, 1-decyneismetabolizedto electrophilic metabolites whereas 3- and 5-decynes are essentially not [36, 37]. 

Atkinson et al. [73] have described the photochemical addition of 3-hexyne and 5-decyne to benzonitrile. The products were 2,3-diethylcyclooctatetraene-l-carbonitrile and 2,3-n-butylcyclooctatetraene-l-carbonitrile, respectively. The ortho addition apparently takes place at positions 1 and 2 of benzonitrile. Subsequent ring opening of the initial bicyclo[4.2.0]octa-2,4,7-trienes leads to the 1,2,3-trisubstituted cyclooctatetraenes. 

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