Construction of Enantioenriched [3.1.0] Bicycles via a Ruthenium-Catalyzed Asymmetric Redox Bicycloisomerization Reaction

Abstract

Enantiomerically enriched [3.1.0] bicycles containing vicinal quaternary centers were synthesized from [1,6]-enynes using a cyclopentadienylruthenium catalyst containing a tethered chiral sulfoxide. The reaction was complicated by the fact that the substrates contained a racemic propargyl alcohol that could affect the selectivity of the process. Nonetheless, high levels of enantioinduction were observed, despite complications arising from the use of racemic substrates. Mechanistic studies showed that while the utilization of either enantiomer of the propargyl alcohol led to high product enantiomeric ratios when the reaction was conducted in acetone, a significant matched/mismatched effect was observed in tetrahydrofuran.

Auto‐Tandem Catalysis: Activation of Multiple, Mechanistically Distinct Process by a Single Catalyst

“…Another example of the utility of chiral ruthenium catalysts in asymmetric ATC process was recently reported by Trost et al (Scheme ) . Ruthenium‐catalysed redox isomerisation of propargyl alcohols 35 gave ruthenium carbenoids 36 .…”

Enantioselective One‐pot Synthesis of 3‐Azabicyclo[3.1.0]hexanes via Allylic Substitution and Oxidative Cyclization

“…To summarize, an enantioselective one‐pot synthesis of azabicyclo[3.1.0]hexanes 1 from propargyl amines 2 and allyl carbonates 3 was established with organocatalyzed allylic substitution and Pd(II)/Pd(IV)‐SPRIX‐mediated oxidative cyclization. Further applications and biological assay of the obtained 1 are currently underway in our laboratory.…”

Organic Synthesis. Use of Alkynes as a Key to Innovation in Designing Structure for Function

“…During our studies of redox isomerization, we discovered an isomerization of a propargyl alcohol to an α,β,–unsaturated carbonyl group, as shown in eq 2 where we applied the process to the synthesis of leukotriene…”