General Reactivity of 2-Lithiobenzothiazole to Various Electrophiles and the Use as a Formyl Anion Equivalent in the Synthesis of α-Hydroxy Carbonyl Compounds
demonstrated by its reaction with phenacyl halides and 5-chloro-2-pentanone leading to the formation of benzothiazolyl-substituted small-ring ethers. In order to demonstrate the value of 2-lithiobenzothiazole as a masked formyl anion, 2-(α-hydroxyalkyl)benzothiazoles were transformed into α-hydroxy carbonyl compounds in three reaction steps without masking the α-hydroxygroups. Quaternization of various
Metal-free deprotonative functionalization of heteroaromatic compounds was achieved using an organic superbase catalyst; an organosilicon additive such as trimethylsilylpropyne was employed for activating the catalytic cycle of 1,2-addition to carbonyl compounds.
Onium amides, generated in situ from the combination of aminosilanes and onium fluorides (R(4)PF, R(4)NF), are employed for the first time as bases for catalytic deprotonative functionalization of C(sp(2))-H and activatedC(sp(3))-H bonds under mild conditions.