Efficient Two-Step Synthesis of Salicylaldehydes via Directed <i>ortho</i>-Lithiation of in situ N-Silylated <i>O</i>-Aryl <i>N</i>-Isopropylcarbamates
作者:Dieter Hoppe、Matthias Kauch
DOI:10.1055/s-2006-926461
日期:2006.5
O-Aryl N-isopropylcarbamates, conveniently prepared from phenols and isopropyl isocyanate, are subjected to an efficient ortho-lithiation protocol to afford the corresponding salicylaldehydes in a one-pot operation in high yields.
Unusual Kinetic Profiles for Lewis Base-Catalyzed Sulfenocyclization of ortho-Geranylphenols in Hexafluoroisopropyl Alcohol
作者:Kevin A. Robb、Soumitra V. Athavale、Scott E. Denmark
DOI:10.1055/s-0039-1690111
日期:2019.9
The kinetic behavior of the Lewis base-catalyzed sulfenocyclization of polyenes in hexafluoroisopropyl alcohol (HFIP) was explored. The rate of reaction is not dependent on the electronic properties of the terminal nucleophile, suggesting that this capture step is not rate limiting. Additionally, fractional orders were observed for two of the reaction components. This intriguing profile appears unique
Synthesis of Halogenated Phenols by Directed <i>ortho</i>-Lithiation and <i>ipso</i>-Iododesilylation Reactions of <i>O</i>-Aryl <i>N</i>-Isopropylcarbamates
作者:Dieter Hoppe、Matthias Kauch
DOI:10.1055/s-2006-926462
日期:2006.5
The regioselective synthesis of halogenated phenols via directed ortho-lithiation reactions of in situ N-silylated O-aryl N-isopropylcarbamates is reported. This protocol is complemented by ipso-iododesilylation reactions of C-silylated carbamates and iodine-magnesium exchange reactions, which are facilitated by the adjacent carbamoyl group. These methods provide an entry into a series of o-fluoro-