Thermodynamically favored aldol reaction of propargyl or allenyl esters: regioselective synthesis of carbinol allenoates.

Ten β-allenic esters, ketones, and thioesters 15 bearing alkyl, alkenyl, aryl, and trimethylsilyl groups are synthesized in 57- 85% yield by 1,6-addition of organocuprates to polarized enynes 10. The dependence of the regioselectivity of the protonation of the allenyl enolate intermediate 7 on the protonating agent is studied: pure allenes are obtained by quenching the intermediate with pivalic acid at −80°C. The method is applied in a short synthesis of pseudoionone (18).

Synthesis of allenes by 1,6-addition of organocuprates to polarized enynes

A variety of highly substituted 2(3H)-furanones are readily prepared from 3-alkynoate esters and the corresponding acids via electrophilic cyclization. Successful electrophiles in this process include I2, ICl, and PhSeCl. This highly efficient process proceeds under mild conditions, tolerates various functional groups, and generally provides substituted 2(3H)-furanones in good to excellent yields.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=16077&context=rtd

Synthesis of 2(3H)-furanones via electrophilic cyclization.

Enantioselective preparation of allenecarboxylates by asymmetric horner-wadsworth-emmons reaction

The results of kinetic studies on the uncatalyzed [3,3]-sigmatropic rearrangement of 2-alkoxycarbonyl-substituted allyl vinyl ethers are reported. Apparently first reported by Gosteli in 1972, this variation of a Claisen rearrangement enjoyed a shadowy existence for three decades until its potential for the development of a catalytic asymmetric Claisen rearrangement was discovered. Inspired by this development, we have studied substituent and solvent rate effects, and we provide evidence that a chairlike transition state is highly favorable for the uncatalyzed Gosteli-Claisen rearrangement.

Gosteli-Claisen rearrangement: substrate synthesis, simple diastereoselectivity, and kinetic studies.

Synthesis and claisen rearrangement of 1-allyloxy-1-carbomethoxy allenes

Severe COVID-19 induces DAD, a condition with temporal-spatial heterogeneity. We determined the differentially expressed genes (DEGs) in the histological patterns of DAD. Twelve fatal COVID-19 cases were classified in acute DAD (n=5) and intermediate/advanced (IA) DAD (n=7). Autopsy lung RNA was extracted from COVID-19 and 4 control cases. RNA sequencing was performed on the Illumina NovaSeq 6000. Enrichment analysis was performed with clusterProfiler using Genome-wide annotation for Human R package. GO terms and KEGG pathways were considered enriched if adjusted p≤0.05. Principal component analysis showed that IA-DAD samples were grouped, while acute DAD samples were scattered. The differential expression analysis between these two groups and the control cases revealed: 261 DEGs in the acute DAD (143 Up- and 53 Down-regulated), 244 DEGs in the IA- DAD tissues (67 Up- and 116 Down-regulated), and 61 DEGs were shared between them (45 Up- and 16 Down-regulated). Patients with acute DAD had up-regulated genes related to oxidative phosphorylation, blood coagulation, megakaryocytes differentiation/regulation, and platelet degranulation/activation. Patients with IA-DAD had DEGs related to immunoglobulins and extracellular matrix. The shared up-regulated DEGs between both patterns are involved in innate and adaptive immune responses. We selected 3 DEGs in each DAD pattern for validation by real-time PCR. There were no differences in acute DAD DEGs, but DEGs overexpressed in intermediate DAD (COL3A1, IGLV3-19, IGHV1-58) were significantly higher. Genes related to thrombotic events occur at the acute stage of DAD, whereas immunoglobulin production and remodeling occur at later stages of DAD. 

M.J. Sleeman

Papers

Synthesis and claisen rearrangement of 1-allyloxy-1-carbomethoxy allenes

Differentially expressed genes in Diffuse Alveolar Damage (DAD) patterns of COVID-19.