Metal free catalytic hydroboration of multiple bonds in methanol using N-heterocyclic carbenes under open atmosphere
作者:Kun Wen、Jinbo Chen、Feng Gao、Pinaki S. Bhadury、Erkang Fan、Zhihua Sun
DOI:10.1039/c3ob41499j
日期:——
An easy to operate method of catalytic hydroboration of unsaturated compounds has been developed with wide substrate scope. Reactions of various aldimines, ketimines, α,β-unsaturated carbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboron and N-heterocyclic carbenes in methanol without requiring a transition metal or inert atmosphere.
Highly Selective Methods for Synthesis of Internal (α-) Vinylboronates through Efficient NHC–Cu-Catalyzed Hydroboration of Terminal Alkynes. Utility in Chemical Synthesis and Mechanistic Basis for Selectivity
作者:Hwanjong Jang、Adil R. Zhugralin、Yunmi Lee、Amir H. Hoveyda
DOI:10.1021/ja2007643
日期:2011.5.25
procedures (1 mol % catalyst loading). Mechanistic studies are presented, indicating that α selectivity arises from the structural and electronic attributes of the NHC ligands and the alkyne substrates. Consistent with suggested hypotheses, catalyticreactions with a Cu complex, derived from an N-adamantyl-substituted imidazolinium salt, afford high β selectivity with the same class of substrates and under
Copper-catalyzed hydroboration of propargyl-functionalized alkynes in water
作者:Jessie S. da Costa、Roger K. Braun、Pedro A. Horn、Diogo S. Lüdtke、Angélica V. Moro
DOI:10.1039/c6ra14465a
日期:——
The Cu-catalyzed hydroboration of alkynes in operationally simple and environmentally friendly conditions is reported. The reactions are performed in water, at room temperature, under micellar catalysis. Conditions to form the α or β borylated products selectively have been found and as an application a protocol for the tandem hydroboration/Suzuki coupling in water was developed.
Stereocomplementary Syntheses of 1,ω‐Distannylated<i>E</i>,<i>Z</i>‐Isomeric Conjugated Trienes, Tetraenes, and Pentaenes
作者:Jochen Burghart、Achim Sorg、Reinhard Brückner
DOI:10.1002/chem.201001629
日期:2011.5.27
Stereoselective syntheses of 1,6‐bis(tributylstannyl)hexa‐1,3,5‐trienes, 1,8‐bis(tributylstannyl)octa‐1,3,5,7‐tetraenes, and 1,10‐bis(tributylstannyl)deca‐1,3,5,7,9‐pentaenes with various methylation patterns were achieved based on stereocomplementary CC bond‐forming reactions. All‐E isomers resulted from Ramberg–Bäcklund rearrangements of distannylated diallyl‐, allylpentadienyl‐, or bis‐ (pentadienyl)sulfones
trans-dimethylbicyclo[4.3.0]nonane and 7-isopropylenecyclohepta-1,3,5-triene. The latter unique structure, in which all carbon atoms are sp2 hybridized, is not found in other triterpenoids and needs to be verified synthetically. Herein, we have accomplished the first total synthesis of lancilactone C (proposed structure) by developing a new domino [4 + 3] cycloaddition reaction involving oxidation, Diels–Alder
Lancilactone C 是一种三环三萜类化合物,可抑制 H9 淋巴细胞中人类免疫缺陷病毒 (HIV) 的复制,且无细胞毒性。其三环骨架由反式-二甲基双环[4.3.0]壬烷和7-异丙烯环庚-1,3,5-三烯组成。后者独特的结构,即所有碳原子都是sp2杂化,是其他三萜类化合物中没有发现的,需要合成验证。在此,我们通过开发一种新的多米诺骨牌[4 + 3]环加成反应,包括氧化、Diels-Alder反应、消除和电环化,首次全合成了lancilactone C(拟定结构)。我们还根据兰西内酯 C 的合理生物合成途径,在其全合成的基础上修改了结构。