Sonogashira coupling carbonylative

Cao H, McNamee L, Alper H (2008) Syntheses of substituted 3-methyleneisoindolin-1-ones by a palladium-catalyzed sonogashira coupling-carbonylation-hydroamination sequence in phosphonium salt-based ionic liquids. Org Lett 10(22) 5281-5284... 

In the presence of tetramethyltin, 1-bromonauclefine reacts with CO in a Pd-catalyzed carbonylation to give the alkaloid naucletine [202], Dong and Busacca effected a new synthesis of tryptamines and tryptophols via a Rh-catalyzed hydroformylation of functionalized anilines that are prepared by a standard Heck reaction, as shown for the preparation of tryptamine sulfonamide 325 [423]. This reaction is applicable to ring-substituted tryptamines (Cl, Br, F. OMe, CF3). Likewise, the Rh-catalyzed carbonylation of o-alkynylanilines, which were prepared by a Pd-catalyzed Sonogashira coupling, leads to oxindoles (60-86% yields) [424],... 

A palladium-catalysed carbonylative Sonogashira coupling was successfully carried out in the same setup [35]. Aryl iodides and phenylacetylene were submitted... 

Very recently Ryu and coworkers disclosed radical carbonylation/Sonogashira coupling sequences (Fig. 44) [218]. The reaction is applicable to primary, secondary, and tertiary alkyl iodides 177, and terminal aryl or alkyl alkynes 185. Alkynyl... 

Fig. 44 Tandem carbonylation/Sonogashira coupling sequences of alkyl halides...

A highly efficient synthesis of l-alkylidene-l,3-dihydrobenzo[f]furans from t>-hydroxymethyl iodoarenes and propargyl alcohols uses a bimetallic Pd/Cu-catalyzed Sonogashira coupling/cyclization reaction (Equation 132) <1999SL456>. Pd/l,4-bis(diphenylphosphino)butane (DPPB)-catalyzed reaction of t>-allylphenols under a CO atmosphere leads to carbonylative cyclization to form benzannulated lactones <2006ASC1855>. A similar carbonylative cyclization leads to the stereoselective formation of 3-alkenyl phthalides <2006T4563>. 

A carbonyl group in conjugation with the triple bond exerts a strong polarization of the alkyne. Thus, Sonogashira coupling of acid chlorides 7 and terminal alkynes... 

A couple of years ago we have disclosed a new mode of alkyne activation towards isomerization as a detouring outcome of the Sonogashira coupling. As a result of coupling electron deficient (hetero)aryl halides (or a,p-unsaturated p-halo carbonyl compounds) 11 and aryl propargyl alcohols 12 a new access to 1,3-di (hetero)aryl propenones 13, i.e., chalcones, was established (Scheme 9) [77, 78]. The scope for electron deficient (hetero)aromatic halides 11 is fairly broad and even organometallic complexes like 13c can be synthesized by this sequence. 

Ahmed MSM, Mori A (2003) Carbonylative sonogashira coupling of terminal alkynes with aqueous ammonia. Org Lett 5 3057-3060... 

Ahmed, M. S. M., Mori, A. Carbonylative Sonogashira Coupling of Terminal Alkynes with Aqueous Ammonia. Org. Lett. 2003, 5, 3057-... 

The Pd-catalysed intramolecular carbonylative lactonisation of 2-acetoxy-2 -iodobiaryls takes on additional significance when combined with the iodocycHsation of 2-(2-acetoxyphenyl)-l-(2-methoxyphenyl)ethyne. Thus, coumestans are obtained in excellent overall yield in two steps following a Sonogashira coupling of a 2-ethynylanisole and a 2-iodophenyl acetate <05JOC9985>. 

The first palladium-catalyzed carbonylative Sonogashira coupling was reported in 1981 by Kobayashi and Tanaka [25]. Aryl, heterocyclic, and vinylic halides reacted with CO and terminal acetylenes at 120 °C and 80 bar in the presence of NEta and a catalytic amount of a palladium(II) complex to form alkynones in a 46-93 % yield (Scheme 5.3). Remarkably, aryl bromides and aliphatic alkynes were also included in the range of substrates. But NEts was used as a solvent for this transformation and a relatively high pressure of CO was needed. 

Interestingly, in 1991 Alper and Huang described another type of palladium-catalyzed carbonylative Sonogashira coupling of aryl iodides with benzyl acetylenes. Here, furanones were isolated as the terminal products and not the predicted alkynones [26]. In the presence of Pd(OAc)2/PPh3, aryl iodides and benzyl acetylenes were transformed into furanones in 33-88 % yields (Scheme 5.4). Palladium-catalyzed carbonylative Sonogashira coupling reactions of iodobenzene and... 

Scheme 5.3 First Pd-catalyzed carbonylative Sonogashira coupling of organic halides...

In 1991 Ortar and colleagues published a general procedure for tbe carbonylative Sonogashira couplings of vinyl triflates with terminal acetylenes [28]. Various alkynyl ketones were produced in moderate to good yields (Scheme 5.5). However, this methodology failed in the case of activated alkynes or aryl triflates. 

The catalytic ability of dimeric palladium hydroxide in carbonylative Sonogashira coupling was demonstrated by Alper and his team in 1994 [29]. In this report, terminal alkynes and alkynols were coupled with aryl iodides in the presence of carbon monoxide in moderate to good yields (Scheme 5.6). In 1995 Cacchi and colleagues presented a general methodology for 5-(2-acylethynyl)-... 

Scheme 5.6 Dimeric palladium hydroxide-catalyzed carbonylative Sonogashira coupling...

Another example of carbonylative Sonogashira coupling reactions with iodi-nium iodide and 1-alkynes was published by Ma and colleagues in 2001 [32]. Under mild conditions, iodine-substituted alkynones were produced in good yields (Scheme 5.9). Both aromatic, aliphatic and heterocyclic terminal acetylenes can be applied as their substrates. 

---