62837-59-6Relevant articles and documents
Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
supporting information, p. 5611 - 5615 (2019/08/01)
The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
On the effect of backbone modifications in 3,3-dimethyl-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxole
Santschi, Nico,Matthey, Coraline,Schwenk, Rino,Otth, Elisabeth,Togni, Antonio
supporting information, p. 1925 - 1931 (2015/03/18)
We report on the effect of small side-chain modifications to the structure of 3,3-dimethyl-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxole (1b) on its reactivity, as expressed by the initial rate v0 in a model reaction, and show how the latter can be successfully correlated to an easily determined physical parameter p, a 13C NMR chemical shift. The relationship v0～ p is already present in the simplest starting material devoid of the hypervalent bond and the iodine core and, therefore, presents an interesting approach towards the future scaffold-optimization of this class of reagents. The reactivity of hypervalent-iodine-based trifluoromethylating agents, as expressed by the initial rate v0 in a model reaction, correlates to an easily determined physical parameter p, a 13C NMR chemical shift.
Factors affecting migration of tertiary alkyl groups in reactions of alkylboronic esters with bromomethyllithium
Elliott, Mark C.,Smith, Keith,Heulyn Jones,Hussain, Ajaz,Saleh, Basil A.
, p. 3057 - 3064 (2013/06/27)
The reactions of bromomethyllithium with tert-alkylboronic esters could be of great potential for the formation of quaternary carbon centers but often give poor yields/conversions. Calculations and experimental evidence show that tert-alkyl groups migrate less effectively than other types of alkyl group in such reactions and that O-migration competes. Furthermore, slow/incomplete capture of the bromomethyl reagent by the boronic ester is a problem in more hindered systems, and an additional competing reaction, possibly Li-Br exchange on the bromomethylborate species, also leads to lower yields of migrated products. Based on this, experimental protocols have been devised in which the competing reactions are largely suppressed, leading to higher conversions to migrated product for several substrates.
