Titanocene-catalyzed metallation of propargylic acetates in homopropargyl alcohol synthesis

The titanium-catalyzed metallation and subsequent carbonyl addition of propargylic acetates enable the direct formation of homopropargylic alcohols in good yields. The corresponding products were obtained as single regioisomers without the corresponding allene adducts observed.     

Construction of multifunctional heterocycles bearing aza-quaternary carbons by titanocene-catalyzed umpolung reactions

The combined application of Grignard/Reformatsky addition and the titanocene-catalyzed umpolung α-amino carbon-carbon bond formations provided a flexible and versatile protocol for preparation of multifunctional pyrrolidinones/piperidinones/N-Boc-piperidines bearing aza-quaternary carbons (AQC) from cyclic imides and analogues. Based on these multifunctional single-ring motifs, several advanced AQC-bearing heterocycles, such as AQC-possessing indolizidines and 1-azaspirocycles, have been constructed efficiently.