Preparation and synthetic use of heterobimetallic alkyne complexes
thesisposted on 2018-11-13, 12:38 authored by Anthony J. Fletcher
This thesis describes the use of heterobimetallic alkyne complexes for use in an efficient stereoselective variant of the Pauson–Khand reaction. Unlike previous protocols found in the literature the source of chiral control upon cyclisation arises solely from the inherently chiral CoMoC2 core of these complexes and not from an external source. The inherently chiral Co(CO)3MoCp(CO)2- and desymmetrised Co2(CO)5(PPh3)–alkyne complexes were utilised as efficient chiral auxiliaries for nucleophilic additions to remote centres of complexed propargylic aldehydes to form secondary propargyl alcohols with a degree of diastereocontrol. A new procedure for the preparation of Co(CO)3MoCp(CO)2–alkyne complexes has also been addressed in which an adaptation of previously known methodology was devised for rapid and robust synthesis negating specialist techniques and procedures. The diastereoselective complexation of Co2(CO)7(PPh3) with a range of chiral alkynols has also been demonstrated with the view to bring about a stereoselective catalytic PK reaction procedure. Chapter 1 [is] an overview to the uses of dicobalt–alkyne complexes in the literature and developments in this field Chapter 2 highlights our research into the use of heterobimetallic-alkyne complexes for use in organic synthesis. Chapter 3 provides experimental data for our studies.
EPSRC (project studentship).