Regioselective Zirconophosphination of 1-Alkenes: A Versatile Route for the Synthesis of β-Functionalized Alkyldiphenylphosphine Oxides in the Presence of CuCl

Advantages of Group 4 Metallocene Bis(trimethylsilyl)acetylene Complexes as Metallocene Sources Towards Other Synthetically used Systems

Active species for synthetic and catalytic applications are formed from well defined complexes or mixtures of compounds. For group 4 metallocenes, three pathways for the formation of the reactive complex fragment [Cp'2M] are known: (i) reductive mixtures and well defined complexes which are able to form the metallocene fragments either by (ii) addition or (iii) substitution reactions. In this account for each of theses systems (i)-(iii) a prominent example will be discussed in detail, (i) the Negishi reagent Cp2ZrCl2/n-BuLi, (ii) bis(η5 : η1-pentafulvene) complexes and (iii) metallocene bis(trimethylsilyl)acetylene complexes, to show the advantages and the disadvantages for each of these methods for synthetic applications. This account summarizes some main advantages of group 4 metallocene bis(trimethylsilyl)acetylene complexes as metallocene generating agents over other synthetically used systems. For each of the special purposes, all described systems have advantages as well as disadvantages. The aim of this overview is to help synthetic chemists in selecting the most effective system on the basis of [Cp'2M] (M=Ti, Zr) for synthetic or catalytic puposes.

Copper-mediated reaction of oxazirconacyclopentenes with dichlorophenylphosphine: a new pathway for the formation of 1,2-oxaphosphole derivatives

CuCl-mediated reaction of oxazirconacyclopentenes with dichlorophenylphosphine afforded dihydrooxaphospholes in high yields, in which the reaction was performed conveniently in one-pot from an alkyne, carbonyl compound and dichlorophosphine.