Highly Stereoselective Facile Synthesis of 2-Acetoxy-1,3(<i>E</i>)-alkadienes via a Rh(I)-Catalyzed Isomerization of 2,3-Allenyl Carboxylates

A highly stereoselective Rh(I)-catalyzed 1,3-acetoxyl rearrangement of 1,2-allen-3-yl carboxylates leading to 2-acetoxy-1,3(E)-alkadienes has been developed. In addition to the high catalytic efficiency and the scope, the excellent E-selectivity of the double bond is remarkable

High Diastereoselectivity in Intermolecular Carbonyl Ylide Cycloaddition with Aryl Aldehyde Using Methyl Diazo(trifluoromethyl)acetate

Methyl diazo(trifluoromethyl)acetate undergoes Rh2(OAc)4 catalyzed reaction with aryl aldehyde to form 1,3-dioxolanes bearing a C-4 trifluoromethyl group diastereoselectively in excellent yield

Highly Stereoselective Facile Synthesis of 2-Acetoxy-1,3(<i>E</i>)-alkadienes via a Rh(I)-Catalyzed Isomerization of 2,3-Allenyl Carboxylates

A highly stereoselective Rh(I)-catalyzed 1,3-acetoxyl rearrangement of 1,2-allen-3-yl carboxylates leading to 2-acetoxy-1,3(E)-alkadienes has been developed. In addition to the high catalytic efficiency and the scope, the excellent E-selectivity of the double bond is remarkable

Synthesis of Polysubstituted Furans Based on a Stepwise Sonogashira Coupling of (Z)-3-Iodoalk-2-en-1-ols with Terminal Propargylic Alcohols and Subsequent Au(I)- or Pd(II)-Catalyzed Cyclization−Aromatization via Elimination of H₂O

Recently, we have developed highly regio- and stereoselective carbometalation of 2-alkynols and 2,3-allenols. The organometallacyclic intermediates may be trapped with I2 to afford 3-iodoalk-2-en-1-ols. These 3-iodoalk-2-en-1-ols may readily undergo the Sonogashira coupling with terminal propargyl alcohols to form 4-alkyn-2-ene-1,6-diols. Subsequent cycloisomerization in DMA or CH2Cl2 with Au(PPh3)Cl and AgOTf as the catalyst would afford polysubstituted 2-(1-alkenyl)furans; with PdCl2 as the catalyst and the reaction in DMA in the presence of allylic bromides, the same substrates afforded polysubstituted 2-(1,4-alkadienyl)furans. In both types of catalyzed cyclization reactions, the elimination of H2O promoted the aromatization to form the furan ring. Different alkyl or aryl groups could be introduced into different positions of furans due to the substituent-loading capability of 3-iodoalkenols and diversity of the terminal propargyl alcohols and allylic bromides

PCR amplification of the positive control.

<p>Note: (a) Amplification results for the cotton endogenous reference gene <i>Sad 1</i>; M: 100-bp marker. (b) Amplification results for the cotton exogenous gene <i>G2</i>-<i>aroA</i>; M: Trans2K^TM DNA marker. 1: ddH₂O; 2: Island cotton 7124; 3: Upland cotton K312; 4: Transgenic cotton BG2-7; 5: Plasmid DNA.</p

Sequences of primers used in this study.

<p>Sequences of primers used in this study.</p

Synthesis of Polysubstituted Furans Based on a Stepwise Sonogashira Coupling of (Z)-3-Iodoalk-2-en-1-ols with Terminal Propargylic Alcohols and Subsequent Au(I)- or Pd(II)-Catalyzed Cyclization−Aromatization via Elimination of H₂O

Recently, we have developed highly regio- and stereoselective carbometalation of 2-alkynols and 2,3-allenols. The organometallacyclic intermediates may be trapped with I2 to afford 3-iodoalk-2-en-1-ols. These 3-iodoalk-2-en-1-ols may readily undergo the Sonogashira coupling with terminal propargyl alcohols to form 4-alkyn-2-ene-1,6-diols. Subsequent cycloisomerization in DMA or CH2Cl2 with Au(PPh3)Cl and AgOTf as the catalyst would afford polysubstituted 2-(1-alkenyl)furans; with PdCl2 as the catalyst and the reaction in DMA in the presence of allylic bromides, the same substrates afforded polysubstituted 2-(1,4-alkadienyl)furans. In both types of catalyzed cyclization reactions, the elimination of H2O promoted the aromatization to form the furan ring. Different alkyl or aryl groups could be introduced into different positions of furans due to the substituent-loading capability of 3-iodoalkenols and diversity of the terminal propargyl alcohols and allylic bromides

Controllable Highly Stereoselective Reaction of <i>in situ</i> Generated Magnesium Dienolate Intermediates with Different Electrophiles

In this paper, we have described an efficient controllable stereoselective α-acylation and -allylation reaction of the magnesium dienolate intermediates generated in situ from the Fe(III)-catalyzed reaction between 2,3-allenoates and Grignard reagents with different electrophiles to afford 2-acylated or allylated 3(Z)- or (E)-alkenoates depending on the nature of the electrophiles and reaction conditions. The distinct stereoselectivity may be caused by the isomerization of metallic Z-1,3-dienoate to E-1,3-dienoate via the intermediacy of anti-allylic MgCl and syn-metallic species

Structure of Exogenous Gene Integration and Event-Specific Detection in the Glyphosate-Tolerant Transgenic Cotton Line BG2-7 - Fig 3

<p><b>Amplification results for intraspecific specific qualitative PCR using 5ʹ-F3/5ʹ-R1 (a) and 3ʹ-F6/3ʹ-R12 (b).</b> M: Trans2K^TM DNA marker; 1: ddH₂O; 2: Island cotton 7124; 3: Upland cotton K312; 4: Transgenic cotton BG2-7.</p

Controllable Highly Stereoselective Reaction of <i>in situ</i> Generated Magnesium Dienolate Intermediates with Different Electrophiles

In this paper, we have described an efficient controllable stereoselective α-acylation and -allylation reaction of the magnesium dienolate intermediates generated in situ from the Fe(III)-catalyzed reaction between 2,3-allenoates and Grignard reagents with different electrophiles to afford 2-acylated or allylated 3(Z)- or (E)-alkenoates depending on the nature of the electrophiles and reaction conditions. The distinct stereoselectivity may be caused by the isomerization of metallic Z-1,3-dienoate to E-1,3-dienoate via the intermediacy of anti-allylic MgCl and syn-metallic species