Ruthenium-Catalyzed Cyclocarbonylation of Allenyl Alcohols and Amines:  Selective Synthesis of Lactones and Lactams

Abstract

Allenyl alcohols such as 4-hydroxybuta-1,2-dienes and 5-hydroxypenta-1,2-dienes having a variety of substituents undergo cyclocarbonylation in the presence of a ruthenium catalyst under mild conditions selectively to give five- and six-membered lactones in a high yield with 100% atom economy. 5-Aminopenta-1,2-dines are also cyclocarbonylated to give gamma-lactams. A possible carbonylation mechanism involving a ruthenium cluster intermediate is proposed on the basis of experimental results.

C–H amination/cyclocarbonylation of allene carbamates: a versatile platform for the synthesis of α,β-unsaturated γ-lactams

“…The cyclocarbonylation of acyclic allenic amines has been previously described, but the scope of the reaction was quite limited and only sparsely substituted products were obtained. 8,11,12 In addition, the bicyclic nature of the unsaturated lactam produced as a result of cyclocarbonylation (Scheme 2) means that the stereochemistry of R 3 group could be used to effectively dictate the stereochemistry of subsequent manipulations of these scaffolds. 18 A variety of metal carbonyls were explored to promote the reaction and Ru 3 (CO) 12 was found to be most effective.…”

“…18 A variety of metal carbonyls were explored to promote the reaction and Ru 3 (CO) 12 was found to be most effective. Ligands for Ru, including Ar/BIAN (BIAN¼bis(aryl)acenaphthenequinonediimine) were briefly explored, but did not improve the reaction as compared to Ru 3 (CO) 12 alone. 19 Optimization studies showed that as little as 1 mol % of the catalyst could be utilized, with an optimal temperature of 80 C. Higher temperatures resulted in a greater overall conversion, but also greater amounts of decarboxylated byproducts (see Table 2).…”

Synthetic Approaches to α,β‐Unsaturated δ‐Lactones and Lactols

“…Scheme 18. Ruthenium-catalyzed cyclocarbonylations of allenyl alcohols to provide five-and six-membered unsaturated lactones have also been described by Takahashi. [47] Although only three examples of six-membered unsaturated lactones have been described by the authors, this method appears to be an interesting alternative to previously discussed methScheme 19. Scheme 20. odologies (Scheme 19).…”

Straightforward Synthesis of 2(5H)-Furanones as Promising Cross-Coupling Partners: Direct Furanone Annulation Utilizing Ti-Mediated Aldol Addition

“…A literature survey using SciFinder ® revealed a two recent syntheses of 4a; (i) Ru-catalyzed CO insertion into the corresponding allenic alcohol [4]; and (ii) SeBr-resin-mediated lactonization of β,γ-unsaturated carboxylic acids, followed by three oxidation (H 2 O 2 )-elimination-methylation (MeI/LDA) reaction sequences [5]. The first method requires three steps and special handling techniques and/or apparatuses using CO.…”