External chiral ligand-induced enantioselective lithiation/SE2 reactions of isochroman and phthalan
摘要:
Treatment of isochroman and phthalan with a t-BuLi/chiral bis(oxazoline) complex followed by reaction with carbon-electrophiles such as benzaldehyde and CO2 is shown to afford the a-substituted derivatives in moderate-to-high enantioselectivities (up to 97% ee and 83% ee, respectively). The asymmetric induction is proved to occur at the post-lithiation step. (C) 2000 Elsevier Science Ltd. All rights reserved.
Hydroxy group directed stereochemistry in oxypalladation of chiral allylic alcohol
摘要:
Stereochemistry of oxypalladation for epsilon-hydroxy chiral allylic alcohol is described, anti- and syn-face selective syn-oxypalladation to a chiral allyl alcohol takes place and provides enantiomerically opposite 2-(Z)-alkenyl and 2-(E)-alkenyl substituted oxacyclic rings in a ratio of 2:3. (C) 2015 Elsevier Ltd. All rights reserved.