An N-propargyl pyrroloimidazolone with syn stereochemistry derived from L-proline serves as a starting material for the diastereoselective synthesis (> 95:5 dr) of propargyl alkynes or allenamides by direct quench of its lithiated intermediate with alkylating agents or aldehydes/ketones, respectively. Use of the epimeric anti pyrroloimidazolone starting material results in reversal of stereochemistry at the propargyl position in the products, without the need to prepare a separate substrate from D-proline. Lithiation of the syn pyrroloimidazolone and quench with prochiral benzaldehydes without prior transmetalation gives allenamides with crystallographically verified atypical stereochemistry of the benzylic alcohol in > 95:5 dr. The epimeric series of benzylic alcohols may also be obtained in > 95:5 dr by employing transmetalation with chlorotitanium triisopropoxide prior to aldehyde quench. Density Functional Theory (DFT) computational studies provide a rationale for the change in benzylic alcohol stereochemistry by virtue of differing stereofacial attack in 6,5-bicyclic (Li) or 6-membered (Ti) transition states.

A variety of enantiomerically enriched tetrahydrofuran spirocyclic derivatives have been synthesised by a sequential enantioselective proline‐induced stereospecific resolution through aldol reaction of (E/Z)‐(phenylsulfanyl)cycloalkanecarbaldehydes followed by a ketone reduction, acid‐catalysed [1,2]‐SPh stereospecific migration, and ring‐closure reaction.

The reaction between configurably stable -lithiated oxiranes (and aziridines) and 3-substituted cyclobutanones allows to obtain enantiomerically enriched cyclobutanols (er > 98:2). These adducts, subjected to base-mediated Payne rearrangement lead to...