Microwave-Assisted NBS Bromination ofp-Iminotoluenes: Preparation of New Alcohol, Mercapto, and Amino Protection Groups

A more sustainable Wohl–Ziegler bromination: Versatile derivatization of unsaturated FAMEs and synthesis of renewable polyamides

“…Moreover, the allylic bromination was also carried out in bulk to avoid any solvent waste. Notably, microwave assisted allylic brominations of methyloleate or Wohl–Ziegler brominations on water did not lead to the desired monoallylic bromide, which is in contrast to results reported for other substrates (e.g., benzylic substrates) . Furthermore, we observed that mainly a conventional bromination of the double bond occurred in the microwave mediated brominations, most probably due to the faster decomposition of AIBN or NBS, which resulted in higher bromine concentrations.…”

A Tripodal Benzylene-Linked Trisamidophosphine Ligand Scaffold: Synthesis and Coordination Chemistry with Group(IV) Metals

“…For the synthesis of an F -type ligand, three strategies were considered, namely, (i) metalation of N -protected o -toluidine at the benzylic position and subsequent reaction with a phosphorus electrophile (PCl 3 , P­(OPh) 3 ), (ii) synthesis of tris( o -nitrobenzyl)-phosphine and subsequent reduction, and (iii) synthesis of an N-protected primary o -aminobenzyl-phosphine and subsequent reaction with the corresponding N-protected o -aminobenzyl bromide. In preliminary experiments, route (iii) was identified as the most promising approach as ( o -phthalimido)-benzyl bromide reacts cleanly with primary phosphines. However, preparation of the key building block, ( o -phthalimido)-benzyl-phosphine, proved to be more difficult than expected, although a potentially explosive procedure for the preparation of o -aminobenzyl-phosphine was optimized successfully (see the Supporting Information).…”

“…However, preparation of the key building block, ( o -phthalimido)-benzyl-phosphine, proved to be more difficult than expected, although a potentially explosive procedure for the preparation of o -aminobenzyl-phosphine was optimized successfully (see the Supporting Information). In an attempt to prepare ( o -phthalimido)-benzyl-phosphine starting from ( o -phthalimido)-benzyl bromide and NaPH 2 , no primary phosphine, but a small amount of tris( o -phthalimido­benzyl)-phosphine, i.e., the phthaloyl-protected ligand scaffold ( 1-Phth ), was isolated (Scheme ). Treatment of NaPH 2 with 3 equiv of ( o -phthalimido)-benzyl bromide in the presence of 2 equiv of sodium tert -butanolate in THF afforded 1-Phth in low yields (approximately 10%).…”

“…However, unambiguous proof for this assumption cannot be provided; therefore, theoretical values are given without subtraction of a carbon atom. The starting materials ( o -phthalimido)-benzyl bromide, NaPH 2 , Bn 3 TiCl, MCl 4 ­(THF) 2 (M = Ti, Zr, Hf), and Bn 2 Mg­(thf) 2 were synthesized according to published procedures. The dimethylamido precursors M­(NMe 2 ) 4 (M = Ti, Zr, Hf), n -butyl lithium solutions (2.5 M in hexanes), sodium tert -butanolate, and hydrogen chloride solutions (2.0 M in Et 2 O) were purchased from Aldrich and used as received.…”