The Catalytic Enantioselective Claisen Rearrangement of an Allyl Vinyl Ether

Catalysis of the Claisen Rearrangement of Aliphatic Allyl Vinyl Ethers

“…The [Cu II box]-catalyzed Claisen rearrangement of the 6,6-dimethyl-substituted allyl vinyl ethers 3iϪn was studied first (Scheme 20, Table 5). [34] Scheme 20. [Cu II (box)](OTf) 2 -catalyzed enantioselective Claisen rearrangement As detailed in Table 5, the [Cu(Ph-box)](OTf) 2 complex 13 catalyzes the Claisen rearrangement with very good enantioselectivity and outstanding chemoselectivity.…”

Triphenyl(prop-2-yn-1-yl)silane

“…For background to silane chemistry, see: Abraham et al (2001Abraham et al ( , 2003; Helmboldt & Hiersemann (2003); Hiersemann (1999Hiersemann ( , 2000; Nelson et al (2011). Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009 …”

“…Silane acts as an intermediate en route to alkoxy-carbonyl substituted allyl vinyl ethers (Hiersemann, 2000), which exhibit a wide range of reactivity for further synthetic transformation (Hiersemann, 1999;Abraham et al, 2001;Abraham et al, 2003;Helmboldt et al, 2003;Nelson et al, 2011) developed in our laboratory.…”

Gold(I)‐Catalyzed Desymmetrization of 1,4‐Dienes by an Enantioselective Tandem Alkoxylation/Claisen Rearrangement

“…[5] Thus we endeavored to develop al igand-controlled enantioselective alkoxylation/Claisen rearrangement. [6] [*] H. Wu, [+] We envisioned that an enantioselective variant might be available through ad esymmetrization reaction [7,8] of 1,4dienes.R ecently,g old-catalyzed enantioselective desymmetrization by nucleophilic addition to alkynes has been reported either through differentiation of enantiotopic alkynes [9] or nucleophiles. [10] In contrast, successful implementation of ad esymmetrization strategy to the tandem alkoxylation/3,3sigmatropic rearrangement reaction does not rely on enantiocontrol of the nucleophilic addition because this step forms achiral intermediate A.Rather,the proposed mechanism and the chirality transfer experiment suggest that the catalysts must exert influence over the sigmatropic rearrangement [11,12] event and thus differentiate between enantiotopic transition states B and B' ' (Figure 2b)O nt he basis of this intriguing possibility,herein we describe our efforts to develop agold(I)catalyzed asymmetric tandem alkoxylation/Claisen rearrangement reaction enabled by as trategic desymmetrization of 1,4-dienes ( Figure 2b).…”