Propiolic alcohol

Synonyms Ethynol carbinol acetylene carbinol propiolic alcohol 2-propyn-l-ol 2-propynyl alcohol... 

Synonyms Acetylene carbinol Ethynyl carbinol Ethynyl methanol 1-Hydroxy-2-propyne 3-Hydroxy-1-propyne Propiolic alcohol 1-Propyne-3-ol Propyn-1-ol 1-Propyn-3-ol 2-Propynol 2-Propyn-1-ol 3-Propynol 2-Propynyl alcohol Classification Unsat. aliphatic alcohol Empirical C3H4O Formula HC=CCH20H... 

Propenoic acid, polymers, homopolymer. See Polyacrylic acid 2-Propenylacrylic acid. See Sorbic acid [(2-Propenyloxy) methyl] oxirane. See Allyl glycidyl ether Propiolic alcohol. See Propargyl alcohol Propionic acid... 

The direct combination of selenium and acetylene provides the most convenient source of selenophene (76JHC1319). Lesser amounts of many other compounds are formed concurrently and include 2- and 3-alkylselenophenes, benzo[6]selenophene and isomeric selenoloselenophenes (76CS(10)159). The commercial availability of thiophene makes comparable reactions of little interest for the obtention of the parent heterocycle in the laboratory. However, the reaction of substituted acetylenes with morpholinyl disulfide is of some synthetic value. The process, which appears to entail the initial formation of thionitroxyl radicals, converts phenylacetylene into a 3 1 mixture of 2,4- and 2,5-diphenylthiophene, methyl propiolate into dimethyl thiophene-2,5-dicarboxylate, and ethyl phenylpropiolate into diethyl 3,4-diphenylthiophene-2,5-dicarboxylate (Scheme 83a) (77TL3413). Dimethyl thiophene-2,4-dicarboxylate is obtained from methyl propiolate by treatment with dimethyl sulfoxide and thionyl chloride (Scheme 83b) (66CB1558). The rhodium carbonyl catalyzed carbonylation of alkynes in alcohols provides 5-alkoxy-2(5//)-furanones (Scheme 83c) (81CL993). The inclusion of ethylene provides 5-ethyl-2(5//)-furanones instead (82NKK242). The nickel acetate catalyzed addition of r-butyl isocyanide to alkynes provides access to 2-aminopyrroles (Scheme 83d) (70S593). 

Ammonium sulfide, 3, n Ammonium thiocyanate, 7, 48 Ammonolysis, 4, 3 7, 16 o-Amyl alcohol, 1, 4, 10 Amyl alcohol, active, 7, 77 mo-Amyl Bromide, 1,1, 2, 4, 10 w-Amyl Methyl Ketone, 7, do -Amyl propiolic acid, 7, 62 Analysis of Benzoylhydroperoxide, 8,32 Analysis of Benzoylperoxide, 8, 31 Anhydro-o-Hydroxymercoribenzoic Acid, 7, 3... 

A Baylis-Hillman type product has been obtained through a ring-opening reaction of an epoxide with an allenoate <06OL2771>. The reaction of MgL, with ethyl propiolate provides the iodo allenoate 32. This nucleophile reacts with an aryl epoxide to provide the homoallylic alcohol 33. The Z iodide is the major product formed. 

Figure 6.27. Conjugate addition of benzyl alcohol to methyl propiolate catalysed by a fluorous phosphine...

Propenyl acetate, a74 2-Propenylamine, a74 Propenylanisole, ml07 2/-2-Propenyl-2-propen-1 -amine, d30 (2-Propenyl)thiourea, a97 Propiolic acid, p248 Propyl alcohol, p201... 

It is also possible to carry out a substrate-controlled reaction with aldehydes in an asymmetric way by starting with an acetylene bearing an optically active ester group, as shown in Eq. 9.8 [22]. The titanium—acetylene complexes derived from silyl propiolates having a camphor-derived auxiliary react with aldehydes with excellent diastereoselectivity. The reaction thus offers a convenient entry to optically active Baylis—Hillman-type allyl alcohols bearing a substituent (3 to the acrylate group, which have hitherto proved difficult to prepare by the Baylis—Hillman reaction itself. 

Similarly phenyl propiolic acid is first reduced to phenyl propargyl alcohol which then forms a complex with LiAlH4 and decomposition of the latter with water gives cinnamyl alcohol. 

As shown in Scheme 1, aliphatic phosphines such as P(n-Bu)3 catalyze the addition of alcohols (2) to methyl propiolate (3) [35]. The mechanism is believed to involve an initial addition of the phosphine to the C = C moiety to give a zwitterionic allenolate (I), which then deprotonates the alcohol, yielding a vinyl phosphonium salt (II). An alkoxide addition to give an enolate (III), followed by phosphine elimination gives the product 4 and regenerates the catalyst. Several experiments suggest that when alcohols are used in excess, the catalyst rests as the original phosphine [34]. 

Scheme 1 Phosphine-catalyzed addition of alcohols (2) to methyl propiolate (3)...

Wilson and Tebby have studied the reaction of triphenylphosphine with different acetylenic esters in alcohol medium and have shown that /3-alkoxyvinylphosphonium ylides and vinyl ethers are formed through the alcoholysis of vinyl phosphonium intermediates. Thus, triphenylphosphine reacts with DMAD in methanol to give the phosphorane (432) [Eq. (62)]. The reaction with propiolic esters, on the... 

When 303 was directly treated with Me2Cu(CN)Li2, the transmetallation failed to discriminate between the two carbon-metal bonds. By contrast, the allylzincation of the alkynyllithium derived from the propargylic alcohol 309 produced the alkenyl 1,1-dimetallic species 310, in which the two carbon-metal bonds exhibit different reactivities due to the presence of a metal-alkoxide. Indeed, transmetallation with Me2Cu(CN)Li2 led to the alkenyl copper-zinc species 311, which was relatively poorly reactive towards electrophiles but underwent successful 1,4-addition to ethyl propiolate leading to 312 in satisfactory overall yield (equation 145)180. 

The iV-aminopyrrole - benzene ring methodology has been applied to a synthesis of the 9,10-dihydrophenanthrene juncusol (218) (81TL1775). Condensation of the tetralone (213) with pyrrolidine and reaction of the enamine with ethyl 3-methoxycarbonylazo-2-butenoate gave pyrrole (214). Diels-Alder reaction of (214) with methyl propiolate produced a 3 1 mixture of (215) and its isomer in 70% yield. Pure (215) was reduced selectively with DIBAL to the alcohol, reoxidized to aldehyde, and then treated with MCPBA to generate formate (216). Saponification to the phenol followed by O-methylation and lithium aluminum hydride reduction of the hindered ester afforded (217), an intermediate which had been converted previously to juncusol (Scheme 46). 

The intramolecular, radical-mediated cyclization of oj-halo-/ -alkoxyacrylates (formed from propiolates and >-halo alcohols) gives nearly quantitative yields of THF and tetrahy-dropyran ring systems (equation 184)660. The reaction is performed in refluxing benzene in the presence of BusSnH and AIBN. The functionalization in the 2-positions allows for further structural elaboration. Other similar radical cyclizations have also been performed as the key step in natural product synthesis661-663. 

In the reaction of 2-(hexahydropyrimidin-2-ylidene)cycloalkanone 247 and alkyl propiolate for 20-40 hours, after addition and cis-trans isomerization, the spiro intermediates 248 suffered ring cleavage by the attack of a molecule of alcohol to give alkyl 6-oxo-1,2,3,4-tetrahydro-6//-pyrido[ 1,2-a]pyrimidine-9-alkanoates 249 (Scheme 19) (87CB1803, 87TL1527). 

Modified guanidines 3 efficiently catalyzed the asymmetric Michael addition of a prochiral glycine derivatives with acrylate, acrylonitrile and methyl vinyl ketone under simple and mild conditions. Remarkably, both product formation and enantioselectivity were dramatically improved using solvent-free conditions (Scheme 12) [34]. The addition of alcohols to methyl propiolate was performed using fluorous phosphines such as P[(CH2)2 (CF2)7 CF3]3 and again better yields of 99% have been obtained under solvent-free conditions. Toluene was added to efficiently separate the product from the solid catalyst, which was then reused without loss of activity [35],... 

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