Heteroarylation of Congested α-Bromoamides with Imidazo-Heteroarenes and Indolizines via Aza-Oxyallyl Cations: Enroute to Dibenzoazepinone and Zolpidem Analogues.

Herein, we report a highly efficient and unprecedented approach for heteroarylation of congested α-bromoamides via electrophilic aromatic substitution of imidazo-heteroarenes and indolizines under mild reaction conditions (room temperature, metal, and oxidant free). The participation of an in situ generated aza-oxyallyl cation as an alkylating agent is the hallmark of this transformation. The method was readily adapted to synthesize novel imidazo-heteroarene-fused dibenzoazepinone architectures of potential medicinal value.

Desymmetrization of N-Cbz glutarimides through N-heterocyclic carbene organocatalysis.

Over the past decade, the catalysis of N-heterocyclic carbenes has achieved significant advances. In this area, aldehydes, enals, and esters, are commonly employed as starting materials through various catalytic activation modes. However, NHC-activated strategy of amide and its derivatives remains elusive. Described herein is the realization of asymmetric desymmetrization of N-Cbz glutarimides with alcohols through an imide C-N bond cleavage under NHC organocatalysis. A structurally diverse set of enantioenriched 4-amido esters is generated with acceptable yields and high enantioselectivities. This method features mild reaction conditions, excellent substrate scope, and excellent atom economy. DFT calculations have been performed to explore the detailed reaction mechanism and the origin of the enantioselectivity, which indicate that the strength of the C-H···O hydrogen bond and C-H⋯π interactions should be responsible for the stereoselectivity. The current strategy could open a door for efficient construction of (R)-Rolipram with excellent stereoselectivity.

Functional and Radiological Outcome in Distal Third Humerus Fracture Treated with Extra-articular Locking Plate: A Multicentric Retrospective Study.

INTRODUCTION: The optimal method for fixation of extra-articular distal humerus fractures poses a management dilemma. Although various plate configurations have been proposed, anatomic shaped extra-articular distal humerus locking plates (EADHPs) have emerged as a viable solution for these complex injuries. We assessed functional and radiologic outcomes in our retrospective case series of extra-articular distal humerus fractures managed with these plates at different centers in Cuttack, Odisha. MATERIALS AND METHODS: One hundred and ten patients of extra-articular distal humerus fractures, who were operated at various trauma centers between January 2012 and December 2020, were identified. After exclusion, 100 patients were available for the final assessment. All patients were operated with the triceps-reflecting modified posterior approach. Regular functional-radiologic follow-up was done evaluating elbow functionality, fracture union, secondary displacement, nonunion, implant failure, and any complications; Mayo Elbow Performance Score (MEPS) was used for the final functional assessment. RESULTS: Sixty-seven percent of male and 33% of female patients constituted the study group, who had an average follow-up of 18 months. Preoperatively three patients and postoperatively one patient had radial nerve palsy; all had neurapraxia and recovered completely. Overall, 95% of patients were adjudged to have complete radiological union within 3 months; 6% of patients developed nonunion. The mean flexion achieved was 123 + 22, and the mean extension was 4.031 + 6.50; five patients with head injury developed flexion deformity of 45. The average MEPS at the final follow-up was 91 + 9.8. CONCLUSION: Stable reconstruction and early initiation of physiotherapy are utilitarian to envision optimal outcome; the use of precontoured EADHPs has yielded satisfactory results with minimal complications in our hands.

Fluoride-Mediated α-Selective 1,6-Conjugate Addition of Allenic Esters to p-Quinone Methides.

An efficient and expedient fluoride-mediated α-selective 1,6-conjugate addition of allenic esters to para-quinone methides has been developed. The reaction exhibited an excellent substrate scope, and a wide range of α-diarylmethylated allenic esters were obtained in good to excellent yields. It was further shown that the strategy could be extended to isatin-derived quinone methides yielding allenic esters containing 3,3-disubstituted oxindoles. The tert-butyl ester of α-diarylmethylated allenoate was effectively converted into γ-butenolide through a Au/Ag catalyzed cyclization strategy.

Base-mediated 1,6-conjugate addition of the Seyferth-Gilbert reagent to para-quinone methides.

A 1,6-conjugate addition reaction of the Seyferth-Gilbert reagent (SGR) to p-quinone methides is reported. This base-mediated protocol allows rapid access to diarylmethylated diazomethylphosphonates. The reaction proceeds under mild basic conditions, making it a practical approach for the synthesis of diarylmethylated diazomethylphosphonates with a broad substrate scope. Interestingly, the treatment of the conjugate adduct with a catalytic amount of rhodium acetate resulted in the 1,2-aryl migration of the rhodium carbenoid intermediate to generate the corresponding 1,2-diaryl alkenylphosphonates in excellent yields.

Rapid and selective synthesis of spiropyrazolines and pyrazolylphthalides employing Seyferth-Gilbert reagent.

An unexpected product-selectivity in the reaction of 2-arylideneindane-1,3-dione with dimethyl diazomethylphosphonate leading to the formation of two different types of products is reported. The reaction carried out in acetone in the presence of catalytic amount of cesium fluoride afforded spiropyrazoline phosphonates via 1,3-dipolar cycloaddition reaction, whereas the reaction in methanol yielded an interesting class of pyrazolylphthalides. This strategy provides an efficient alternative method for the construction of pyrazolylphthalides, and moreover, the process is general, works under mild conditions, and exhibits high functional group compatibility.

Substrate-controlled product-selectivity in the reaction of the Bestmann-Ohira reagent with N-unprotected isatin-derived olefins.

A mild and efficient reaction of the Bestmann-Ohira reagent with N-unprotected isatin-derived olefins has been developed for the selective synthesis of spiro-pyrazoline-oxindoles and tricyclic pyrazoles. The reaction features an attractive product-selectivity depending on the substituent on isatin-derived olefin. Treatment of 3-aryl/alkylideneoxindoles with BOR afforded spiropyrazoline-oxindoles, whereas 3-phenacylideneoxindoles furnished pyrazoloquinazolinones via a unique ring expansion reaction.

Domino reaction involving the Bestmann-Ohira reagent and α,ß-unsaturated aldehydes: efficient synthesis of functionalized pyrazoles.

A mild, efficient and rapid domino reaction involving the Bestmann-Ohira reagent (BOR) and α,ß-unsaturated aldehydes has been developed for the synthesis of densely functionalized vinylpyrazoles. This reaction demonstrates the dual reactivity of BOR as a homologation reagent as well as a cycloaddition partner, thus constituting a domino reaction in an operationally simple procedure. The application of this efficient synthesis of pyrazoles has been demonstrated for the synthesis of phosphonyl analogues of pyrrolopyrazole alkaloids.