title: Formation of three new bonds and two stereocenters in acyclic systems by zinc-mediated enantioselective alkynylation of acylsilanes, Brook rearrangement, and ene-allene carbocyclization reactions.
abstract: Diastereoisomerically pure (dr > 99:1) and enantiomerically enriched (er up to 98:2) substituted propargyl diols possessing a tertiary hydroxyl group were synthesized in a single-pot operation from simple acylsilanes through a combined catalytic enantioselective alkynylation of acylsilanes, followed by an allenyl-Zn-Brook rearrangement and Zn-ene-allene (or Zn-yne-allene) cyclization reaction. Two remarkable features of these reactions are the near complete transfer of chirality in the allenyl-Zn-Brook rearrangement and the highly organized six-membered transition state of the Zn-ene-allene carbocyclization found by DFT calculations. In this process, three new bonds and two new stereogenic centers are created in a single-pot operation in excellent diastereo- and enantiomeric ratios. DFT calculations show that the allenyl-Zn-Brook rearrangement occurs in preference to the classic [1,2]-Zn-Brook rearrangement owing to its significantly lower activation barrier.
authors.affiliation: The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion-Israel Institute of Technology , Technion City, Haifa 32000, Israel.
authors.forename: Polina
authors.initials: P
authors.lastname: Smirnov
authors.forename: Einat
authors.initials: E
authors.lastname: Katan
authors.forename: Jomon
authors.initials: J
authors.lastname: Mathew
authors.forename: Arseni
authors.initials: A
authors.lastname: Kostenko
authors.forename: Miriam
authors.initials: M
authors.lastname: Karni
authors.forename: Anne
authors.initials: A
authors.lastname: Nijs
authors.forename: Carsten
authors.initials: C
authors.lastname: Bolm
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Apeloig
authors.forename: Ilan
authors.initials: I
authors.lastname: Marek