259738-30-2

Upstream product

• 583-53-9 2,3-dibromobenzene 
• 259738-28-8 2-bromo-1-[1-(4-methylphenylsulfonamido)-3-butyn-4-yl]benzene 
• 259738-26-6 2-bromo-1-(4-methylsulfonyloxybut-1-yn-1-yl)benzene 
• 259738-27-7 2-bromo-1-[4-azido(but-1-yn-1-yl)]benzene 
• 457071-55-5 4-(2-bromo-phenyl)-but-3-ynylamine 
• 116510-00-0 2-bromo-1-(1-hydroxy-3-butyn-4-yl)benzene 
• 124-63-0 methanesulfonyl chloride 
• 259738-29-9 2-(3-hydroxyprop-1-yn-1-yl)-1-[4-(4-methylphenylsulfonamido)but-1-yn-1-yl]benzene 

Downstream Products

• 259738-31-3 5-(4-methylphenylsulfonyl)-5-azabicyclo[8.4.0]tetradeca-1⁽¹⁰⁾,11,13-triene-2,8-diyne 

Relevant academic research and scientific papers

Experiment and Computational Study on the Regioselectivity of Nucleophilic Addition to Unsymmetrical p-Benzynes Derived from Bergman Cyclization of Enediynes

The regioselectivity in addition of nucleophiles to the p-benzyne intermediates derived from unsymmetrical aza-substituted enediynes via Bergman cyclization was studied. Computational studies [using UB3LYP/6-31G(d,p) level of theory] suggest that the p-benzyne intermediate retains its similar electrophilic character at the two radical centers even under unsymmetrical electronic perturbation, thus supporting the predicted model of nucleophilic addition to p-benzyne proposed by Perrin and co-workers (Perrin et al. J. Am. Chem. Soc. 2007, 129, 4795-4799) and later by Alabugin and co-workers (Peterson et al. Eur. J. Org. Chem. 2013, 2013, 2505-2527). However, observed experimental results suggest that there was small but definite regioselectivity (～5-25%), the extent varying with the electronic nature of the substituents. Differential solvated halide ion concentrations around the vicinity of two radical centers arising due to surrounding surface electrostatic potential (computationally calculated) may be one of the possible factors for such selectivity in some of the examined p-benzynes. However, other complicated dynamical issues like the trajectory of the attacking nucleophile to the radical center which can be influenced by electronic and/or steric perturbation of starting enediyne conformation cannot be ruled out. The overall yield of the anionic addition was in the range of 80-99%.

Nitrogen substituted cyclic enediynes: Synthesis, thermal reactivity and coniplexation with metal ions

A number of N-substituted cyclic enediynes (azaenediynes) have been synthesized via Pd(0)-catalysed ene-yne coupling followed by N-alkylation. The simplest of them, a 10-membered monocyclic enediyrie 1, underwent Bergman cyclization (BC) at 23°C with a half-life of 72 h. The kinetics of BC slowed down considerably by fusing a benzene ring onto the enediyne. Several novel bis(azaenediyne)s and bis(diazaenediyne)s 3-6 have been synthesized. Their onset temperatures for BC were lowered under metal ion complexation conditions. The Royal Society of Chemistry 2000.

Studies on Bergman cyclization, the chemistry at the heart of enediynes

The kinetics of Bergman cyclization (BC) which is dependent upon a number of steric and stereoelectronic parameters, have been studied in various nitrogen-substituted cyclic enediynes. The simplest of these, a 10-membered enediyne 33 cyclized spontaneously (t1/2 = 72 h at 23°) and caused significant cleavage of supercoiled double stranded DNA at micromolar level. The degree of pyramidalization of the ring nitrogen in these enediynes has an inverse effect on the rate of cyclization. Replacement of the ene part with an aromatic ring led to a considerable elevation of activation energy for BC.