Wharton-Fragmentation-Based Approach to the Carbocyclic Core of the Phomoidrides

Abstract

The carbocyclic core of the phomoidrides has been synthesized efficiently and in high yield. Key steps include a phenolic oxidation/intramolecular Diels-Alder sequence, tandem radical cyclization, and a late-stage Wharton fragmentation of a densely functionalized isotwistane skeleton.

Natural Products with Anti‐Bredt and Bridgehead Double Bonds

“…Utilizing this mode of analysis, specifically concentrating on the degree of distortion (t), selected X-ray crystal structures of the all-carbon series (i.e., 44, 71, 76, and 116; Figure 41) [166] and Clive. [167] Thus compounds 211 and 212 ( Figure 42) were evaluated together with the above chosen natural products ( Figure 41 and Table 1).…”

“…It was also isolated from C. stricta and C. tamariscifolia. [113] A subsidiary publication by this group disclosed cystoseirols B (164), C (165), D (166), and E (167; Figure 30), which are also found in various sources of Cystoseiraceae, that is, C. mediterranea (Banyuls sur Mer), C. tamariscifolia (Atlantic coasts), and C. stricta (Nice), around France. [114] Francisco and co-workers specifically commented that they had identified a natural product that "contains a bridge-head, anti-Bredt, double bond", which was (paradoxically) "in a large enough system to be accommodated", but interestingly no citation to the work of Bredt was provided.…”

Naturstoffe mit Anti‐Bredt‐ und Brückenkopf‐Doppelbindung

“…Von kleineren Ringsystemen gibt es derzeit noch keine Röntgenkristallstrukturen. Zugänglich aus den Arbeiten von Nicolaou,43a Wood166 und Clive et al 167. waren uns jedoch Röntgenstrukturen von Zwischenstufen kurz vor den Phomoidriden (mit vollständigem Bicyclo[4.3.1]‐System).…”

Copper/Silver-Mediated Cascade Reactions for the Construction of 2-Sulfonylbenzo[b]furans from trans-2-Hydroxycinnamic Acids and Sodium Sulfinates

“…1f was prepared by monobenzylation of 2,4-dihydroxybenzaldehyde followed by Horner–Wittig reaction. Recrystallization from EtOH/H 2 O; light-yellow solid, 757 mg (56%), mp 188–190 °C; 1 H NMR (400 MHz, acetone- d 6 ) δ 10.44 (br s, 1H), 9.15 (s, 1H), 7.94 (d, J = 16.0 Hz, 1H), 7.32–7.56 (m, 6H), 6.60–6.62 (m, 2H), 6.47 (d, J = 16.0 Hz, 1H), 5.13 (s, 2H); 13 C NMR (100 MHz, acetone- d 6 ) δ 168.7, 162.7, 158.9, 141.0, 138.0, 131.1, 129.4, 128.8, 128.5, 116.2, 115.9, 108.1, 103.3, 70.6; HRMS (ESI) m / z [M + H] + calcd for C 16 H 15 O 4 271.0965, found 271.0960.…”