1a R1 = R2 = Pri THF, room temp. THF, 70 °C THF–HMPA, 70 °C THF, room temp. ... Philip Jones, Nicolas Millot and Paul Knochel* Fachbereich Chemie der Universität, Hans-Meerwein Strasse, D-35032 Marburg, Germany. E-mail: knochel@ps1515.chemie.uni-marburg.de ... Received (in Liverpool, UK) 29th July 1998, Accepted 22nd September 1998 ... The preparation of allylic zinc reagents using the fragmenta- tion of sterically hindered tertiary homoallylic alcohols ...