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For terminal alkynes it is sometimes important to mask the acidic hydrogen atom. This normally proceeds from deprotonation (via a strong base like methylmagnesium bromide or butyllithium in tetrahydrofuran/ dimethylsulfoxide ) and subsequently reaction with chlorotrimethylsilane to a terminally TMS-protected alkyne. [ 95 ]
Hydroaluminations of terminal alkynes typically produce terminal alkenylalanes as a result. Selectivity in hydroaluminations of internal alkynes is typically low, unless an electronic bias exists in the substrate (such as a phenyl ring in conjugation with the alkyne).
Terminal alkynes have the formula RC≡CH, where at least one end of the alkyne is a hydrogen atom. An example is methylacetylene (propyne using IUPAC nomenclature). They are often prepared by alkylation of monosodium acetylide. [4] Terminal alkynes, like acetylene itself, are mildly acidic, with pK a values of around 25.
Alkyl phosphates belong to a group of organic compounds called organophosphates. They are esters of phosphoric acid H 3 PO 4 and corresponding alcohol. For example, the formula of methyl phosphate is CH 3-H 2 PO 4, dimethyl phosphate – (CH 3) 2 HPO 4 and trimethyl phosphate – (CH 3) 3 PO 4. Alkyl phosphates are widely distributed in nature ...
The name comes from mix of propene and argentum, which refers to the typical reaction of the terminal alkynes with silver salts. The term homopropargylic designates in the same manner a saturated position on a molecular framework next to a propargylic group and thus two bonds from an alkyne moiety. [1]
It is a terminal alkyne, in fact the smallest that is liquid at room temperature. The compound is a common terminal alkyne substrate in diverse studies of catalysis. The compound is a common terminal alkyne substrate in diverse studies of catalysis.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
The coupling of a terminal alkyne and an aromatic ring is the pivotal reaction when talking about applications of the copper-promoted or copper-free Sonogashira reaction. The list of cases where the typical Sonogashira reaction using aryl halides has been employed is large, and choosing illustrative examples is difficult.