We report a Pd-catalyzed halocyclization of unactivated 1,6-diynes with N-bromosuccinimide (NBS). This approach produces stereo-defined dibromo substituted dihydropyrans, tetrahydropyridines, and 3-methylene cyclohexenes with exocyclic double bond appendages in mostly good yields. Copper salt was found to be a useful Lewis acid in this reaction. Mechanistically, a formal anti-carbopalladation and a
我们报告了未活化的1,6-二炔与N-溴代琥珀酰亚胺(NBS)的Pd催化卤代环化反应。这种方法可生产立体定义明确的二溴取代的二氢吡喃,四氢吡啶和3-亚甲基环己烯,并带有环外双键附件,且收率很高。发现铜盐是该反应中有用的路易斯酸。从机理上讲,提出了一种形式上的抗碳氢键合和溴化物自由基促进的Pd II -Pd III -Pd I -Pd II催化循环,参与了二溴取代产物的形成。将二氢吡喃衍生物进一步官能化后进行B(C 6 F 5)3-催化的开环并还原得到具有优异立体选择性的二溴代1,3-二烯。
A convergent formal [4 + 2] cycloaddition of 1,6-diynes and benzyl azides: construction of spiro-polyheterocycles
作者:Ming Bao、Wei Lu、Han Su、Lihua Qiu、Xinfang Xu
DOI:10.1039/c8ob00735g
日期:——
A convergent formal [4 + 2] cycloaddition reaction for the construction of structurally appealing spiro-tetrahydroquinolines has been developed, in which, a one-pot reaction is established for the in situ generation of two reagents, a cyclic alkyne and an N-aryliminium ion, from the corresponding precursors in the presence of an Au-catalyst and Brønsted acid, respectively.
Synthesis of the cyclopentadienone rhodium complexes and investigation of their catalytic activity in the reductive amination of aldehydes in the presence of carbon monoxide
作者:Roman A. Pototskiy、Oleg I. Afanasyev、Yulia V. Nelyubina、Denis Chusov、Alexander R. Kudinov、Dmitry S. Perekalin
DOI:10.1016/j.jorganchem.2017.02.014
日期:2017.5
[(cod)RhCl]2 in the presence of CO gives the cyclopentadienone complex [(Cpd’)Rh(CO)Cl]n (Cpd’ = TsN(CH2)2C4(Tol)2CO). Its dissolution in DMSO or pyridine leads to decarbonylation and formation of the adducts (Cpd’)Rh(DMSO)2Cl and (Cpd’)Rh(Py)2Cl. The reaction of [(Cpd’)Rh(CO)Cl]n with AgPF6 and p-xylene produces the sandwich arene complex [(Cpd’)Rh(p-xylene)]PF6, in which the arene can be substituted
cross-coupling of bromo(iso)quinoline to 1,6-diynes with the Pd-catalyzed system was established. Using unactivated simple diynes with bromo(iso)quinoline in the presence of palladium catalytic system afforded different kinds of rare 7,11-diphenyl-9,10-dihydro-8H-pyrrolo[3,4-j]phenanthridine derivatives through regioselective C–H functionalization in one step. Different diynes (a–p) and different bromo(iso)quinolines
The first examples are described of a convenient domino synthesis of 4,9-diphenyl-2,3-dihydro-1H-benzo[f]isoindole derivatives in a single operation by means of palladium-catalyzed cyclization of simple 1,6-diynes with aryl halides. domino reactions - cyclizations - heterocycles - polycycles - isoindoles
第一个例子描述了通过钯催化简单的1,6-二炔的环化,在一次操作中方便地多米诺合成4,9-二苯基-2,3-二氢-1 H-苯并[ f ]异吲哚衍生物与芳基卤化物。 多米诺反应-环化-杂环-多环-异吲哚