TY - JOUR
T1 - Comparative Diels-Alder reactivities within a family of valence bond isomers
T2 - A biomimetic total synthesis of (±)-UCS1025A
AU - Hoye, Thomas R.
AU - Dvornikovs, Vadims
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2006/3/1
Y1 - 2006/3/1
N2 - A synthesis of the structurally fascinating fungal metabolite UCS1025A (1) was accomplished. It features a likely biomimetic approach to the octalin subunit via an intramolecular Diels-Alder (IMDA) reaction of a putative triene precursor (2), preceded by an efficient construction of the bisheteratriquinane subunit within that compound. Specifically, an intramolecular silyl triflate-induced cyclization of an in situ-generated silyl ketene acetal onto an imide carbonyl group (e.g., 7 to 8) was developed. The IMDA relative reactivities of a family of valence bond isomers, each differing in the precise nature of the dienophilic subunit, were determined. Under biologically relevant conditions (D2O, pH 7.2 buffer, ca. 25 °C), triene 2, via its lactone ring-opened congener, underwent very fast (t1/2 = 10 min) conversion to the ring-opened forms of 1 (i.e., 5a) and the tetraepimeric, alternative endo-adduct, 3 [i.e., (tetraepi)-5a].
AB - A synthesis of the structurally fascinating fungal metabolite UCS1025A (1) was accomplished. It features a likely biomimetic approach to the octalin subunit via an intramolecular Diels-Alder (IMDA) reaction of a putative triene precursor (2), preceded by an efficient construction of the bisheteratriquinane subunit within that compound. Specifically, an intramolecular silyl triflate-induced cyclization of an in situ-generated silyl ketene acetal onto an imide carbonyl group (e.g., 7 to 8) was developed. The IMDA relative reactivities of a family of valence bond isomers, each differing in the precise nature of the dienophilic subunit, were determined. Under biologically relevant conditions (D2O, pH 7.2 buffer, ca. 25 °C), triene 2, via its lactone ring-opened congener, underwent very fast (t1/2 = 10 min) conversion to the ring-opened forms of 1 (i.e., 5a) and the tetraepimeric, alternative endo-adduct, 3 [i.e., (tetraepi)-5a].
UR - http://www.scopus.com/inward/record.url?scp=33644642932&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33644642932&partnerID=8YFLogxK
U2 - 10.1021/ja0581999
DO - 10.1021/ja0581999
M3 - Article
C2 - 16492035
AN - SCOPUS:33644642932
SN - 0002-7863
VL - 128
SP - 2550
EP - 2551
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 8
ER -