1.1- Diethoxy-2-propyne

To a solution of 0.40 mol of butyllithium in about 280 ml of hexane were added 280 ml of dry THF with cooling below -10°C. Subsequently 0.40 mol of 1,1-diethoxy--2-propyne (see Chapter V, Exp. 28) was introduced in 15 min at -30 to -10°C. To the solution obtained was then added in 15 min with cooling at about -15°C 0.40 mol of chloromethyl ethyl ether (note 2). After the addition stirring was continued for 1 h without cooling. The mixture was then shaken with concentrated ammonium chloride solution and the ethereal layer was separated off. The aqueous layer was extracted twice with diethyl ether. After drying the ethereal solutions over magnesium sulfate the diethyl ether was evaporated in a water-pump vacuum. 

Diethoxymethyl)- 1-methanesulfonyl 2-Iodo-iV-(methane- sulfonyl)anilinc 3,3-Diethoxy propyne Pd(PPh,),Cl Cul 63 [2]... 

Propiolaldehyde, 3-chloro-, diethyl acetal (8) 1-Propyne, 1-chloro-3,3-diethoxy- (9) (62761-29-9)... 

Alkynes with EWGs are poor substrates for the coupling with halides. Therefore, instead of the inactive propynoate, triethyl orthopropynoate (350) is used for the coupling with aryl halides to prepare the arylpropynoate 351. The coupling product 353 of 3,3-diethoxy-l-propyne (352) with an aryl halide is the precursor of an alkynal[260]. The coupling of ethoxy(tributylstan-nyl)acetylene (354) with aryl halides is a good synthetic method for the aryl-acetate 355[261J. 

The advantages of lithium acetylides over haloalkynes (in Michaelis-Arbuzov or Michaelis-Becker routes) have been clearly demonstrated in several comparable syntheses. For example, from tlie condensation of 3,3-diethoxy-l-lithio-l-propyne with diethyl chlorophosphate at -65°C, diethyl... 

Synthesis of unsaturated aldehydes. 4-Keto-2-fran,s-hexenal (5), an odoriferous substance secreted by some arthropods, has been synthesized by the reaction of the Grignard derivative of l,1-diethoxy-2-propyne (2) with propanal (1). The product (3) is then reduced specifically with sodium in liquid ammonia to... 

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