475467-02-8Relevant articles and documents
Formal synthesis of palmerolide A, featuring alkynogenic fragmentation and syn-selective vinylogous aldol chemistry
Lisboa, Marilda P.,Jones, David M.,Dudley, Gregory B.
supporting information, p. 886 - 889 (2013/04/10)
An enantioselective route to palmerolide A is described. The approach features original syntheses of three subunits, which are then assembled to produce a known late-stage intermediate and formally provide the highest overall yield of the natural product
Ring opening of cyclic vinylogous acyl triflates using stabilized carbanion nucleophiles: Claisen condensation linked to carbon-carbon bond cleavage
Jones, David M.,Lisboa, Marilda P.,Kamijo, Shin,Dudley, Gregory B.
experimental part, p. 3260 - 3267 (2010/08/19)
Addition of stabilized carbanionic nucleophiles to cyclic vinylogous acyl triflates (VATs) triggers a ring-opening fragmentation to give acyclic β-keto ester and related products, much like those observed traditionally in the Claisen condensation. Unlike in the classical Claisen condensation, however, the VAT-Claisen reaction described herein is rendered irreversible by C-C bond cleavage, not by deprotonation of the activated methylene product. Full details of this original reaction methodology are disclosed herein, including how subtle differences between the various nucleophiles impact the proper choice of reaction conditions for making 1,3-diketones, β-keto esters, and β-keto phosphonates.
Tandem nucleophilic addition/fragmentation reactions and synthetic versatility of vinylogous acyl triflates
Kamijo, Shin,Dudley, Gregory B.
, p. 6499 - 6507 (2007/10/03)
A thorough analysis of the chemistry of vinylogous acyl triflates provides insight into important chemical processes and opens new directions in synthetic technology. Tandem nucleophilic addition/C-C bond cleaving fragmentation reactions of cyclic vinylogous acyl triflates 1 yield a variety of acyclic acetylenic compounds. Full details are disclosed herein. A wide array of nucleophiles, such as organolithium and Grignard reagents, lithium enolates and their analogues, hydride reagents, and lithium amides, are applied. The respective reactions produce ketones 2, 1,3-diketones and their analogues 3, alcohols 4, and amides 5. The present reactions are proposed to proceed through a 1,2-addition of the nucleophile to the carbonyl group of starting triflates 1 to form tetrahedral alkoxide intermediates C, followed by Grob-type fragmentation, which effects C-C bond cleavage to yield acyclic acetylenic compounds 2-5 and 7. The potent nucleofugacity of the triflate moiety is channeled through the σ-bond framework of 1, providing direct access to the fragmentation pathway without denying other typical reactions of cyclic vinylogous esters. The synthetic versatility of vinylogous acyl triflates, including functionalization reactions of the cyclic enone core (1 → 6 or 8), is also illustrated.
