Total Syntheses of Highly Oxidized <i>ent</i>-Kaurenoids Pharicin A, Pharicinin B, 7‑<i>O</i>‑Acetylpseurata C, and Pseurata C: A [5+2] Cascade Approach

The unprecedented oxidative dearomatization-induced [5+2] cycloaddition/pinacol-type 1,2-acyl migration cascade efficiently generates a quaternary carbon center and assembles the highly oxygenated bicyclo[3.2.1]­octane framework of <i>ent</i>-kaurene diterpenoids. By incorporation of the subsequent retro-aldol/aldol process and singlet oxygen ene reaction, this concise and convergent approach has enabled the first asymmetric total syntheses of pharicin A, pharicinin B, 7-<i>O</i>-acetylpseurata C, and pseurata C

Synthesis of 2‑Vinylbenzofurans via the Copper-Catalyzed Multicomponent Reactions Involving an Oxa-Michael/Arylation/Vinylation Cascade

2-Vinylbenzofurans have been synthesized via the copper-catalyzed one-pot, three-component reactions of <i>o</i>-iodophenols, in situ generated allenes, and dichloromethane. Cascade transformation of oxa-Michael addition, C-arylation, and sp³C–H/sp³C–Cl conversion-based vinylation has been involved in realizing the construction of this 2-vinylbenzofuran framework

Genetic dissection of QTLs and differentiation analysis of alleles for heading date genes in rice

<div><p>Heading date is an important agronomic trait in rice (<i>Oryza sativa</i> L.); it determines the geographical and seasonal adaptability of the crop. Single segment substitution lines (SSSLs) have become the preferred experimental materials in mapping functional genetic variations as the particular chromosome segments from donor genotypes can be evaluated for their impact on the phenotype in a recurrent recipient background. The phenotypic differences can be attributed to the control of quantitative trait loci (QTLs). Here, we evaluated a library consisting of 1,123 SSSLs in the same genetic background of an elite rice variety, Huajingxian74 (HJX74), and revealed four SSSLs, W05-1-11-2-7-6 (W05), W08-16-3-2 (W08), W12-28-58-03-19-1 (W12), and W22-9-5-2-4-9-3 (W22), which had a significantly different heading date compared to HJX74. To further genetically dissect the QTLs controlling heading date on chromosomes 3, 6, and 10, four SSSLs were used to develop 15 secondary SSSLs with the smaller substituted segments. The <i>qHD-3</i> heading date QTL detected in W05 and W08 was delimited to an interval of 4.15 cM, whereas <i>qHD-6-1</i> and <i>qHD-6-2</i> heading date QTLs dissected from the substituted segments in W12 were mapped to the intervals of 2.25-cM and 2.55-cM, respectively. The <i>qHD-10</i> QTL detected on the substituted segment in W22 was mapped to an interval of 6.85-cM. The nucleotide and amino acid sequence changes for those genes in the secondary SSSLs were also revealed. The allele variations of those genes might contribute to the heading date QTLs on chromosome 3 (<i>DTH3</i>, <i>OsDof12</i>, and <i>EHD4</i>), chromosome 6 (<i>Hd3a</i>, <i>Hd17</i>, and <i>RFT1</i>), and chromosome 10 (<i>Ehd1</i> and <i>Ehd2</i>). These sequence variations in heading date genes would be useful resources for further studying the function of genes, and would be important for rice breeding. Overall, our results indicate that secondary SSSLs were powerful tools for genetic dissection of QTLs and identification of differentiation in the genes.</p></div

Alignment of Hd17 amino acid sequences from HJX74 and W12-S4.

<p>The green triangles indicate the prematurely terminated coding site in W12-S4, whereas red triangles indicate amino acid substitutions between HJX74 and W12-S4.</p

Putative candidate genes of each QTL.

<p>Putative candidate genes of each QTL.</p

The substituted segments in the four SSSLs and their days to heading in 2014 and 2015.

<p>The substituted segments in the four SSSLs and their days to heading in 2014 and 2015.</p

Mapping intervals and allelic effects of QTLs for heading date in the SSSLs.

<p>Mapping intervals and allelic effects of QTLs for heading date in the SSSLs.</p

Alignment of <i>DTH3</i> coding sequences from HJX74, W05-S2 and W08-S3.

<p>The green triangles indicate the locus of CDS sequence from W08-S3, whereas red triangles indicate the locus of CDS sequence from W05-S2.</p

Genetic dissection and fine mapping of QTLs for heading date on rice chromosome 6.

<p>Genetic dissection and fine mapping of QTLs for heading date on rice chromosome 6.</p

Alignment of Ehd2 amino acid sequences from HJX74 and W22-S2.

<p>The green triangles indicate the start site of frameshift in W12-S4, whereas red triangles indicate amino acid substitutions between HJX74 and W12-S4.</p