L -Butadien

Simple conjugated dienes used in polymer synthesis include 1,3-butadiene, chloroprene (Z-chloro-l -butadiene), and isoprene (2-methyl-l,3-butadiene). Isoprene has been prepared industrially by several methods, including the acid-catalyzed double dehydration of S-methyl-l/S-butanediol. 

Highly c/s-selectivity and low molecular weight distribution polymerization of l -butadiene with cobalt(II) pyridyl bis(imine) complexes in the presence of ethylaluminum sesquischloride effect of methyl position in the ligand... 

Ni l butadiene diene = 1 200 100 reaction temperature 40°C Scheme 2.3-3. Influence of perturbations on Cyclo-cooligomerization... 

In the system nickel/L/butadiene, secondary amines can shift the cyclodimerization of butadiene to the acyclic products (7a) and (75) Its cocatalyst functfon can be visualized by the corresponding [L]-control map (Scheme 3.3-2). In the three-component system nickel/morpholine/butadiene the open-chain products are formed for log ([morpholine]o/[Ni]o) > -1. Both octatrienes (7a) and (75) are formed at the constant ratio of 1.8 over the entire range of the examined amine/nickel scale. However, the efficiency of the catalytic system is low. After a turnover of 30% butadiene, the catalytic activity ends because of the formation of stop complexes of the nickel amide type. 

Chelating 1,4-diaza-l -butadiene ligands (V,[Pg.209]

Both l-(butadien-l, 3 -yl)silatrane (93) and -trialkoxysilane can react by a Diels-Alder-type reaction with tetracyanoethylene (TCNE) or maleic anhydride (MA) to give the corresponding adducts (equations 129 and 130). However, a higher temperature is required for effective conversion of trialkoxysilane355. 

Am Bicyclo[4.4.0]decadien-(1,3) laufen bcidc Reaktionstypen gleiehzeitig ab1, so daB Tricyclo[4.4.0.01 i]decen-(2) und l-Butadien-(l,3)-yl-cyclohexen gebildet werden ... 

---