Efficient synthesis of 2- and 3-substituted indenes from 2-bromobenzyl bromide through an enolate alkylation/Cr(II)/Ni(II)-mediated carbonyl addition sequence
作者:Ronald L. Halterman、Chengian Zhu
DOI:10.1016/s0040-4039(99)01541-5
日期:1999.10
efficient new synthesis of 2- and 3-substituted indenes has been developed based on the nickel-catalyzed chromium(II)-promoted addition of aryl bromides to a tethered ketone carbonyl. Several tethered bromoaryl ketones were prepared through enolatealkylation of acyclic or cyclic ketones with 2-bromobenzyl bromide. Nozaki-Takai-Hiyama-Kishi closure of the resulting bromoaryl ketones followed by acid promoted
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