化学键的选择性断裂在有机化学中始终具有重要意义。在未应变的系统中,强碳-碳σ键的裂解仍然具有挑战性。在这里,我们报道了在相对温和的条件下,负载型金属催化的脂肪族伯醇中碳-碳σ键的选择性氢解。以Ru / TiO 2为模型反应体系进行1-十六烷醇氢解时,观察到碳-碳键相对于碳-氧键的选择性断裂,导致正十五烷为主要产物,少量n-十六烷。理论计算表明,在平面Ru(0001)上的1-十六烷醇氢解经历了两个平行的途径:即碳-碳键断裂产生正十五烷和碳-氧键断裂产生正十六烷。在平坦的Ru(0001)表面上去除吸附的CO是1-十六醇氢解的关键步骤。它有助于覆盖正十五烷生产中的最大能量屏障,并且通过覆盖活性Ru(0001)表面来阻碍正十六烷生产的速率。这项工作中提供的知识不仅对基本的碳-碳σ键断裂有基本的了解,而且对于将生物质实际转化为燃料和化学原料也具有重要意义。
What is described is a compound of formula I
consisting of a compound in which R
1
is a branched chain alkyl consisting of 10 to 31 carbons; R
2
is a linear alkyl, alkenyl, or alkynyl consisting of 2 to 20 carbons; L
1
and L
2
are the same or different, each a linear alkylene of 1 to 20 carbons or a linear alkenylene of 2 to 20 carbons; X
1
is S or O; R
3
is a linear or branched alkylene consisting of 1 to 6 carbons; and R
4
and R
5
are the same or different, each a hydrogen or a linear or branched alkyl consisting of 1 to 6 carbons; or a pharmaceutically acceptable salt thereof.
Chemo- and Regioselective Functionalization of Polyols through Catalytic C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Kumada-Type Coupling of Cyclic Sulfate Esters
作者:Rodrigo Ramírez-Contreras、Bill Morandi
DOI:10.1021/acs.orglett.6b01745
日期:2016.8.5
This contribution describes a copper-catalyzed, C(sp3)–C(sp3) cross-coupling reaction of cyclic sulfate esters, a distinct class of electrophilic derivatives of polyols, with alkyl Grignard reagents to afford functionalized alcohol products in good yields. The method is operationally simple and highlights the potential of cyclic sulfate esters as highly reactive substrates in catalytic, chemoselective
Hindered organoboron groups in organic chemistry. 24. The condensation of aliphatic aldehydes with dimesitylboron stabilised carbanions to give ketones.
作者:Andrew Pelter、Keith Smith、Said M.A. Elgendy、Martin Rowlands
DOI:10.1016/s0040-4020(01)87982-5
日期:1993.8
The condensation of boron stabilised carbanions, Mes2BCHLiR1, (R1≠H) with aliphatic aldehydes, R2CHO, followed by treatment with trifluoroacetic anhydride (TFAA) or N-chlorosuccinimide (NCS) is an unique, broadly applicable redox process that yields ketones, R1CH2COR2, directly and in high yields. The anion Mes2BCH2Li (Mes2BCHLiR1, R1H) gives high yields of alkenes, R2CHCH2 in the same conditions
Catanionic vesicles and DNA complexes: a strategy towards novel gene delivery systems
作者:C. Pucci、A. Scipioni、M. Diociaiuti、C. La Mesa、L. Pérez、R. Pons
DOI:10.1039/c5ra15466a
日期:——
Catanionic vesicles and DNA form complexes, the structure and composition of which depend on the DNA content. The DNA undergoes a reversible compaction process and its release can be triggered by adding an anionic surfactant to the complexes.
Storage-stable, non-sedimenting emulsions comprising a) 10 to 80% by weight, based on the emulsion, of one or more anti-oxidants, b) 0.25 to 10% by weight, based on the emulsion, of a surfactant in the form of a fatty acid salt of formula R-COOY, wherein R is straight chain or branched C.sub.3 -C.sub.18 alkyl or straight chain or branched C.sub.3 -C.sub.18 -alkenyl, or is phenyl(C.sub.3 -C.sub.18)alkyl, and Y is an alkali metal, which salt is prepared in situ from the fatty acid, c) 0.25 to 10% by weight, based on the emulsion, of a co-surfactant in the form of an alcohol of the general formula R'--OH, wherein R' is straight chain or branched C.sub.4 -C.sub.19 alkyl or straight chain or branched C.sub.4 -C.sub.19 alkenyl, or is phenyl(C.sub.4 -C.sub.19)alkyl, and d) water to make up 100%. The emulsions are used for stabilizing emulsion-polymerized polymers and copolymers such as ABS.