Methyl propargyl ether

The flask was charged with 2.0 mol of dry, freshly distilled (note 1) methyl propargyl ether (VIII-6, Exp. 7), potassium iert.-butoxide (note 2) (5 g) was added with stirring and the mixture was heated under reflux. The reaction was... 

Methyl-l-propanethiol, b471 Methyl propargyl ether, m407... 

The indium nonaflate (In(ONf)3)-catalyzed annulation of 2-thienyl- and 2-furylindoles, bithiophenes, and bifurans with methyl propargyl ether also provides tetracyclic heteroaryl annulated [ ]carbazoles in moderate to good yields <2005AGE1336> (Equation (104) Table 10). 

Dimetallation of Methyl Propargyl Ether with BuLi-t-BuOK... 

Reaction of 13-Dipotassiated Methyl Propargyl Ether with Bromohexane... 

The stereochemistry around the double bond was exclusively trans in the case of disubstituted olefins and it was also noteworthy that the hydration of methyl propargyl ether alkynes was regioselective, which was not the case with other alkynes. 

Methyl-1-propanethiol, b389 Methyl propargyl ether, m396... 

Methyl Propargyl Ether from Propargyl Alcohol, Dimethyl Sulfate and NaOH... 

The use of Rh2(5/ -MEPY)4 and Rh2(55-MEPY)4 for reactions with menthyl diazoacetates (MDA) also produces an enormous double diastereoselection not previously observed to the same degree in cyclopropanation reactions. With methyl propargyl ether, for example, Rh2(5/ -MEPY)4 catalyzed reactions of d-MDA yield 16 (R = CH3OCH2) in 98% diastereomeric excess (de), but /-MDA produces its diastereoisomer in only 40% de with Rh2(55-MEPY)4, /-MDA gives the higher de (98%) and d-MDA gives the lower de (43%). Similar results are obtained from reactions of MDA with 1-hexyne and 3,3-dimethyl-1-propyne. The diazocarboxylate substituent obviously plays a critical role in establishing the more effective carbene orientation for addition to the alkyne. 

Benzodithiophenes 840 are synthesized by In-catalyzed annulation of 2,2 -bithiophenes 839 with methyl propargyl ether (Scheme 128) <2005AGE1336>. 

The conversion of a dimeric rr-bound methyl propargyl ether complex [Mo2(CO)4Cp2(At-Tj, i7--CH=CCH20Me)] (35) to the cationic allenyl complex [Mo2(CO)4Cp2(m-i7% i -CH=C=CH2] (36) has been described by Curtis et al. (25). Protonation of 35 with HBF4 induced the loss of methanol and formation of the required complex. Alternatively the same complex was reported accessible via the acid-promoted elimination of methanol from [Mo2(CO)4Cp2 M-T7%Tj -MeO(H)C=C=CH2 ], a rare example of an intact T7%Tj -bound allene (Scheme 9). 

Other examples of preparative routes relying on reactions with electrophiles have been used in the syntheses of thieno[2,3-y][l,2,3,4,5]pentathiepin by treatment of tetrahydrothiophene with S2CI2 in the presence of DABCO <05OBC3496> and indium nonaflate [In(ONf)3] catalyzed annulation of the 2,2 -bithiophene 62 with methyl propargyl ether leading to the system 63 <05AG(E)1336>. 

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