A concise synthesis of (S)-(+)-5,6-2H-pyran-2-one via hydrozirconation–carbonylation–demetallation of O-benzyl (S)-(−)-4-pentyn-2-ol

Catalytic Asymmetric Access to α,β Unsaturated δ-Lactones through a Vinylogous Aldol Reaction: Application to the Total Synthesis of the Prelog-Djerassi Lactone

“…The α,β unsaturated and saturated δ-lactones are found in an impressive number of natural and unnatural products possessing interesting biological activities. − These compounds are also useful chiral building blocks, such as for example the Prelog-Djerassi lactone. , Efficient asymmetric syntheses of such lactones have been described but required the use of a stoichiometric amount of chiral auxiliary and/or a multiple-step sequence. − …”

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

“… Previous work of hydrozirconations with Schwartz's reagent and our work [ 54 – 55 57 – 58 61 – 62 ]. …”

“…Hydrozirconations were also combined with carbonylations to install carbonyl groups. For example, the sequential hydrozirconation/carbonylation of propargylic ethers 18 reported by Donato [ 58 ] yielded α,β-unsaturated lactones 19 . Beside the hydrozirconation/acylation sequence of nitriles utilizing acid chlorides published by Majoral/Floreancig [ 59 – 60 ], Cox revealed that terminal alkynes 16 could be converted to enones 20 by hydrozirconation followed by Pd-catalyzed acylation with acyl chlorides 21 [ 61 ].…”

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

“…Alkynes and allenes are also rich sources of starting materials for some efficient routes to α,β-unsaturated lactones. Dupont has described a one-pot hydrozirconation/carbonylation/lactonization sequence starting from homopropargylic alcohols: during the lactonization step, an equilibrium between the (E)-and (Z)-α,β-unsaturated acyl iodides is involved in the presence of an excess of iodide [46] (Scheme 18). Scheme 18. Ruthenium-catalyzed cyclocarbonylations of allenyl alcohols to provide five-and six-membered unsaturated lactones have also been described by Takahashi.…”