Total Synthesis of Resolvin T4

A total synthesis of resolvin T4 was achieved by connecting three intermediates by Wittig reactions. The enal in the C1–C10 part was constructed through reduction of a propargylic alcohol with Red-Al followed by oxidation. The enal moiety in the C11–C16 part was synthesized by a ring-opening reaction of a silyl epoxide followed by a Peterson elimination. The chiral centers at C7 and C13 were constructed by ruthenium-catalyzed asymmetric transfer hydrogenation.

The Phospha-Bora-Wittig Reaction

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

The Phospha-Bora-Wittig Reaction

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

Wittig Reactions of Maleimide Derived Stabilized Ylides with Alkyl Pyruvates: Concise Approach to Methyl Ester of (±)-Chaetogline A

A facile synthesis of methyl ester of chaetogline A is reported starting from the corresponding methyl 1-methyltryptophanate derived maleimide. A stereoselective Wittig olefination with a carbonyl function in methyl pyruvate followed by phosphorous pentoxide induced regioselective dehydrative cyclization are the essential reactions. An acid induced thermodynamically driven stereoselective β- to α-position migration of the exocyclic carbon−carbon double unit in ethyl tetrahydroindolizinoindolylidenepropanoate is described.

Recent Advances in the Synthesis of Heterocycles by the Aza-Wittig Reaction

The formation of the C=N bond in recent studies on heterocyclic compounds via the aza-Wittig reaction is reviewed. Furthermore, two different strategies for the formation of heterocyclic compounds, including intermolecular and intramolecular aza-Wittig reactions are described. The primary aim of this review is to provide up-to-date information on the application of the aza-Wittig reaction in the synthesis of a wide range of N-containing heterocyclic compounds in the chemical literature since 2010.1 Introduction2 Mechanism of the Staudinger and Aza-Wittig Reactions3 Intramolecular Aza-Wittig Reaction4 Intermolecular Aza-Wittig Reaction5 Conclusion

Interrupted aza-Wittig reactions using iminophosphoranes to synthesize 11C–carbonyls

Iminophosphoranes are coupled with CO2 and carbon-, nitrogen-, oxygen-, and sulfur-based nucleophiles to synthesize acyclic (radio)pharmaceuticals in high yield.

Interrupted Aza-Wittig Reactions Using Iminophosphoranes to Synthesize 11C-Carbonyls

Iminophosphoranes are reported as convenient precursors to amides, ureas, carbamates and other carbonyl-containing molecules through CO2-fixation. Key to this transformation with stable isotopes and carbon-11 is interception of the reactive isocyanate intermediate. Automated synthesis and isolation of PET radiopharmaceuticals is achieved.