טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentKulbitski Kseniya
SubjectNew Approaches and Reagents for the Synthesis of
Halo-Organic Compounds
DepartmentDepartment of Chemistry
Supervisor Professor Mark Gandelman
Full Thesis textFull thesis text - English Version


Abstract

Organic iodides are extremely useful compounds, and novel methodologies for their efficient synthesis is an important goal in organic chemistry. Here is presented a novel, general and robust method for the conversion of carboxylic acids to organic iodides without the use of heavy metals or strong oxidizing agents, by using N-Iodo amides as reagents able to effect both the generation of a radical intermediate and halogen donation under irradiative conditions.

Mechanistic studies were conducted to understand more thoroughly the process. During the mechanistic studies, new methodologies for the synthesis of N-iodo and N-bromo amides are developed. This methodology proved to be versatile and general, and allowed for the preparation water sensitive halo-amides under non-aqueous conditions.

Establishing a new methodology for the synthesis of N-iodo amides allowed for the concomitant development of a new generation of iodinating reagents. These reagents proved to possess superior reactivity and stability than existing reagents. By applying the new reagents in iododecarboxylation reactions, we successfully obtained iododecarboxylation products that could not be obtained with commercially available N-iodoamides.

Our methodology allowed us to prepare geminal dihaloalkanes. These compounds are very attractive as substrates for organic synthesis. The lack of a practical way to prepare these compounds has made progress on their studies uneven. We have prepared diiodo-, bromo(iodo)-, chloro(iodo)-, and fluoro(iodo)alkanes and demonstrated their employment in chemoselective cross-coupling reactions.

As with organic iodides, organic bromides are also used for many applications, such as pharmaceuticals, agriculture, disinfectants, flame extinguishing agents, and dyes. They are desirable for increased stability and lower cost with respect to the corresponding iodides. N‑Bromoamides were successfully used in a new bromodecarboxylation methodology for aromatic carboxylic acids.