the heavier halogens (bromine and iodine) second, the scope and limitations of the halogenative phase‐transfer methodology will be discussed and compared. An extension of the fluorination/semi‐pinacol reaction to the ring‐expansion of five‐membered allylic cyclopentanols will be also described, as well as some preliminary results on substrates prone to desymmetrization will be given. Finally, the present
The present manuscript describes a high-yielding enantioselective semipinacol transposition, initiated by an electrophilic iodination event. The title transformation makes use of the anionic phase-transfer catalysis (PTC) paradigm for chirality induction. Thus, when combined appropriately, the insoluble cationic iodinating reagent S9 and the lipophilic phosphoric acid L9 act as an efficient source
A systematic study of the behaviour of aryl γ-halopropargyl ethers under thermal condition was undertaken. Aryl γ-bromopropargyl ethers underwent unique transformation in N,N-diethylanillne (215°C, 6 h) giving rise to a mixture of products ,and , whereas, under similar conditions aryl γ-chloropropargyl ethers ulbar|8, afforded 4-chlorochromenes, 9. A remarkable substituent and solvent effect has been