Total Synthesis of Polyene Natural Product Dihydroxerulin by Mild Organocatalyzed Dehydrogenation of Alcohols
作者:Hexin Xie、Shilei Zhang、Hao Li、Xinshuai Zhang、Sihan Zhao、Zian Xu、Xixi Song、Xinhong Yu、Wei Wang
DOI:10.1002/chem.201103325
日期:2012.2.20
Polyene synthesis: An efficient approach to the total synthesis of polyene naturalproduct dihydroxrulin (1) is described. A novel, mild, direct organocatalytic IBX‐mediated dehydrogenation process of simple alcohols to enals has been developed, which serves as a key step in the synthesis (see scheme).
Regioselective palladium-catalyzed cross-coupling reactions in the synthesis of novel 2,3-disubstituted thiophene derivatives
作者:Raquel Pereira、Beatriz Iglesias、Angel R de Lera
DOI:10.1016/s0040-4020(01)00764-5
日期:2001.9
A reactivity optimization study of the palladium-catalyzed cross-coupling reactions of 2,3-dibromothiophene and organometallicreagents has been conducted. Regioselectivecoupling at the C2 position, accomplished most notably by Suzuki coupling, was combined with a Stille reaction at C3 using Fu's modification, to afford the 2,3-disubstituted thiophene derivatives.
The CH Activation/1,3-Diyne Strategy: Highly Selective Direct Synthesis of Diverse Bisheterocycles by Rh<sup>III</sup>Catalysis
作者:Da-Gang Yu、Francisco de Azambuja、Tobias Gensch、Constantin G. Daniliuc、Frank Glorius
DOI:10.1002/anie.201403782
日期:2014.9.1
The reactivity and selectivity of 1,3‐diynes in transition‐metal‐catalyzed CH activation is exploited to quickly assemble diverse polysubstituted bisheterocycles, which are highly important but difficult to access. By using the CH activation/1,3‐diyne strategy, we overcame the challenges of selectivity (chemo‐, regio‐, and mono‐/diannulation) and constructed seven kinds of adjacent bisheterocycles
[1,3]-Transfer of Chirality during the Nicholas Reaction in γ-Benzyloxy Propargylic Alcohols
作者:David D. Díaz、Miguel A. Ramírez、Víctor S. Martín
DOI:10.1002/chem.200501127
日期:2006.3.8
gamma-acetylenic diols with BF3 x OEt2 provides bis-homopropargylic alcohols. The reaction occurs within seconds, tolerates a wide range of functionalities, and provides good yields. When the ether group is located at a stereochemically defined carbon atom, the rearrangement occurs with high stereoselectivity, transferring the chirality of the carbinol center to the newly created stereocenter. The cleavage
描述了高度区域和立体选择性的分子内[1,5]-氢转移过程。用BF3 x OEt2处理γ-苄基保护的Co2(CO)6-α,γ-炔二醇可提供双均炔丙基醇。反应在几秒钟内发生,可耐受多种功能,并提供良好的收率。当醚基位于立体化学定义的碳原子上时,重排会以高立体选择性发生,从而将甲醇中心的手性转移至新创建的立体中心。当存在另外的苄基醚时,苄氧基的裂解是完全区域选择性的。评价了该新方法在密集取代的底物中的范围和局限性,还描述了可能的竞争反应和/或立体化学影响。
Preparation and colorimetric response of an aldehyde-functionalized macrocyclic diacetylene-derived polydiacetylene
作者:Hansol Kim、Mohammed Iqbal Khazi、Jong-Man Kim
DOI:10.1016/j.dyepig.2020.109114
日期:2021.3
polydiacetylene (PDA) that is generated by polymerization of the aldehyde-functionalized macrocyclic diacetylene, MCDA-CHO. UV irradiation of self-assembled MCDA-CHO generates a blue-color PDA, which undergoes a sequential blue-purple-brown-orange color change upon heating. Interestingly, the PDA displays a remarkably high temperature reversible thermochromism between 30 (blue) and 180 °C (reddish-brown)