Cooperative Catalysis for the Highly Diastereo‐ and Enantioselective [4+3]‐Cycloannulation of
<i>ortho</i>
‐Quinone Methides and Carbonyl Ylides
作者:Arun Suneja、Henning Jakob Loui、Christoph Schneider
DOI:10.1002/anie.201913603
日期:2020.3.27
We describe herein a highly diastereo- and enantioselective [4+3]-cycloannulation of ortho-quinone methides and carbonyl ylides to furnish functionalized oxa-bridged dibenzooxacines with excellent yields and stereoselectivity in a single synthetic step. The combination of rhodium and chiral phosphoric acid catalysis working in concert to generate both transient intermediates in situ provides direct
A new method for the preparation of 3-isochromanone derivatives is reported. The method consists of the ethoxycarbonylation of o-acylbenzyllithiums with ethylchloroformate and the subsequent NaBH4...
A Novel Tandem [2 + 2] Cycloaddition−Dieckmann Condensation with Ynolate Anions. Efficient Synthesis of Substituted Cycloalkenones and Naphthalenes via Formal [<i>n</i> + 1] Cycloaddition
作者:Mitsuru Shindo、Yusuke Sato、Kozo Shishido
DOI:10.1021/jo015929w
日期:2001.11.1
A noveltandem [2 + 2] cycloaddition-Dieckmanncondensation via ynolate anions is described. Ynolate anions are useful for the formation of reactive beta-lactone enolates via a pathway not involving the enolization of the corresponding beta-lactones. The [2 + 2] cycloaddition of ynolate anions with delta- or gamma-keto esters, followed by Dieckmann condensation, gives bicyclic beta-lactones, which