Propargylic alcohols carbonylation

When the Pd-catalyzed carbonylation with diaryl dichalcogenides and CO is apphed to propargyl alcohols, carbonylative lactonization occurs under higher CO pressure giving /3-(arylchalcogeno)-a,/3-unsaturated y-lactones in good yields (Scheme... 

Aconitatc was obtained as a minor product in the carbonylation of propar-gyl alcohol[479]. However, in the two-step synthesis of methyl aconitate (536) from propargyl alcohol in 70% overall yield, the first step is the oxidative carbonylation under CO and air using Pdli and KI to giNe dimethyl hydro-xymethylbutenedioate (535), which is carbonylated further to give trimethyl aconitate (536) by u.sc of [Pd(Tu)4jl2 as a catalyst[480]. 

As an application of maleate formation, the carbonylation of silylated 3-butyn-l-ol affords the 7-butyrolactone 539[482], Oxidative carbonylation is possible via mercuration of alkynes and subsequent Lransmetallation with Pd(II) under a CO atmosphere. For example, chloromercuration of propargyl alcohol and treatment with PdCF (1 equiv.) under 1 atm of CO in THF produced the /3-chlorobutenolide 540 in 96% yield[483]. Dimethyl phenylinale-ate is obtained by the reaction of phenylacetylene, CO, PdCU, and HgCl2 in MeOH[484,485]. 

Propargylic alcohols are less reactive and their carbonylation proceeds under severe conditions. The Pd-catalyzed carbonylation of propargyl alcohol in the... 

Butynediol is more difficult to polymerize than propargyl alcohol, but it cyclotrimerizes to hexamethylolbenzene [2715-91 -5] (benzenehexamethanol) with a nickel carbonyl—phosphine catalyst (64) with a rhodium chloride—arsine catalyst a yield of 70% is claimed (65). 

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

MEYER - SCHUSTER Propargyl alcohol rearrangement Add catalyzed rearrangement of acetylenic alcohols into o, -unsaturated carbonyl derivatives... 

Later, a nickel-catalyzed cascade conversion of propargyl halides and propargyl alcohol into a pyrone in water was reported. The reaction involved a carbonylation by CO and a cyanation by KCN (Eq. 4.55).96 Recently, Gabriele et al. explored a facile synthesis of maleic acids by palladium catalyzed-oxidative carbonylation of terminal alkynes in aqueous DME (1,2-dimethoxyethane) (Eq. 4.56).97... 

Air-stable palladium(O) catalyst, [(Cy3P)2Pd(H)(H20)]BF4, catalyses carbonylation of propargylic alcohols to generate dienoic acids and esters (equation 167)286. Since propar-gyl alcohols are obtained from carbonyl compounds by acetyhde addition reactions, this sequence constitutes a three-carbon homologation. a-Allenic alcohols are converted to tt-vinylacrylic acids under similar conditions (equation 168)287. 

Muller and co-workers reported the three-component one-pot synthesis of various pyrimidines through the in situ generation of unsaturated carbonyl compounds. The palladium catalyzed coupling of aryl halides bearing electron withdrawing substituents 7 with propargyl alcohols 8 produced unsaturated carbonyl compounds 9 after isomerization, which condensed with amidines 10 to form triaryl pyrimidines 11 . 

Double bonds in conjugation to a carbonyl group and allylic and propargylic alcohols. But the isolated double and triple bonds are inert. 

Substituted propargylic alcohols were found to undergo direct carbonylation to the corresponding butenolides in 67-98% yield (Eq. 9.120) [86]. This reaction requires a catalytic amount of Pd2(dba)3-CHC13 (4%) and l,4-bis(diphenylphosphi-no)butane (8%) in CH2C12 under an atmosphere of CO (600 psi) and H2 (200 psi) at 95 °C for 36 h. The cyclocarbonylation reaction is believed to proceed via an allenyl-palladium intermediate, which is formed by initial insertion of Pd(0) into the C-O bond of the alkynol followed by rearrangement (Scheme 9.25). 

Despite the rich chemistry of 45 [18], the only method for accessing this compound is the oxidation of the corresponding alcohol derived from 2-methyl-2-propen-l-ol or other sources, which can be obtained through multi-step operations. In contrast to the known methods, 45 can be readily derived from 44 and 50 by a simple one-pot operation. Since the propargylic alcohol 50 a is readily accessed from a ketone or aldehyde, realization of the transformation of 50 to 45 through a one-pot procedure provides a novel method for carbonyl olefmation of ketones or aldehydes. 

Despite the rich chemistry of 288 that may be anticipated, " " synthetic methods for this type of compounds are limited to the one involving oxidation of the corresponding alcohols. In contrast, 288 is readily derived from 287 by a simple and one-pot operation. Since propargylic alcohols are readily accessible from ketones or aldehydes, the straightforward transformation from 70 to 288f provides a novel method for carbonyl olefination of ketones and aldehydes. For example, ethisterone, 301, is tolerable to this transformation (route 2, Scheme 16) without any protection of the functional groups to give 302 (Equation (51))." ... 

Besides alkoxy-, amino-, and amidocarbonylation reactions, a carbonylation process using a thiol as nucleophile, that is, thiocarbonylation, has been extensively studied.It has been shown that the thiocarbonylation takes place with 1-alkynes, " " " propargyl alcohols,allenes, " 1,3-dienes, propargylic mesylates, " and bicyclopropylidene . 

Propargyl alcohols also react with the ether of an enol of carbonyls and lactones to give allenic carbonyl compounds [79a-d] (Eq. 58). 

As with allyl alcoholic substituents, propargyl alcoholic substituents that contain at least one hydrogen atom on the alcoholic carbon are also known to undergo enzymatic oxidation to the corresponding a,(3-unsaturated carbonyl metabolites and are fairly toxic [30, 31, 34]. In addition, propargyl alcohols that contain an aromatic... 

Asymmetric reduction of a,f -acetylenic ketones. This borane can be used to reduce 1-deulerio aldehydes to chiral (S)-l-deulerio primary alcohols in 90% optical yields. It also reduces a,/ -acctylcnic ketones to (R)-propargylic alcohols with enantiomeric purity of 73-100%. The ee value is increased by an increase in the size of the group attached to the carbonyl group. The value is also higher in reductions of terminal ynones. Alcohols of the opposite configuration can be obtained with the reagent prepared from (— )-a-pinene. 

Propargyl alcohols By addition of alkyl groups to acetylenic carbonyl compounds (R)-( + )-/-Butyl p-tolylsulfinylacetate, 59... 

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