Five-Step Synthesis of Yaequinolones J1 and J2

Abstract

Scheme 3. Flow-Chart Presentation of the Synthesis of Yaequinolone J2 ASSOCIATED CONTENT Supporting Information. Experimental procedures and characterization data including 1 H and 13 C NMR spectra, IR and high-resolution mass spectral data are given for all compounds as well as a comparison of NMR data with those reported for natural 1 and 2.

Recent Advances in Oxa-6π Electrocyclization Reactivity for the Synthesis of Privileged Natural Product Scaffolds

“…Along these lines, Quinn [42] and more recently Heretsch and Christmann [43] have exploited an organocatalyzed Knoevenagel/oxa-6π electrocyclization cascade towards the Along these lines, Quinn [42] and more recently Heretsch and Christmann [43] have exploited an organocatalyzed Knoevenagel/oxa-6π electrocyclization cascade towards the assembly of pyranopyridone-based natural products [44]. In their streamlined synthesis of yaequinolones J1/J2 (17a-b) in five steps, Heretsch and Christmann reported their efforts in optimizing the 2H-benzopyran forming step catalyzed by EDDA in toluene to prepare substrate 16 in 49% yield (Scheme 5A) [43]. As shown in Scheme 5B, the pyranopyridone scaffold can also be applied directly to the synthesis of 2H-pyran 18 through a Knoevenagel/oxa-6π electrocyclization sequence catalyzed by ytterbium triflate, thus affording a genuinely straightforward synthesis of melicodenine C ( 19) [42].…”

“…In this effort, Yamashita and Hirama had to meticulously optimized the Knoevenagel/oxa-6π electrocyclization cascade to form the pivotal B ring common to all the cortistatin natural products and avoid the formation of undesired structural isomers [41]. Along these lines, Quinn [42] and more recently Heretsch and Christmann [43] have exploited an organocatalyzed Knoevenagel/oxa-6π electrocyclization cascade towards the Along these lines, Quinn [42] and more recently Heretsch and Christmann [43] have exploited an organocatalyzed Knoevenagel/oxa-6π electrocyclization cascade towards the assembly of pyranopyridone-based natural products [44]. In their streamlined synthesis of yaequinolones J1/J2 (17a-b) in five steps, Heretsch and Christmann reported their efforts in optimizing the 2H-benzopyran forming step catalyzed by EDDA in toluene to prepare substrate 16 in 49% yield (Scheme 5A) [43].…”

“…Organics 2021, 2, FOR PEER REVIEW 5 assembly of pyranopyridone-based natural products [44]. In their streamlined synthesis of yaequinolones J1/J2 (17a-b) in five steps, Heretsch and Christmann reported their efforts in optimizing the 2H-benzopyran forming step catalyzed by EDDA in toluene to prepare substrate 16 in 49% yield (Scheme 5A) [43]. As shown in Scheme 5B, the pyranopyridone scaffold can also be applied directly to the synthesis of 2H-pyran 18 through a Knoevenagel/oxa-6π electrocyclization sequence catalyzed by ytterbium triflate, thus affording a genuinely straightforward synthesis of melicodenine C ( 19) [42].…”

Divergent Total Syntheses of Yaequinolone-Related Natural Products by Late-Stage C–H Olefination

“…The group of Christmann successfully synthesized (±)-peniprequinolone, (±)-aflaquinolones E and F, (±)-6-deoxyaflaquinolone E, (±)-quinolinones A and B, and (±)-aniduquinolone C by developing a general method for the construction of N-glycolated 2-aminobenzophenone via aryne insertions into unsymmetrical imides in flow ( Scheme 1 c). 10 …”

“…The authors used an Evans-type chiral auxiliary to provide the syn -aldol diol as a 1:1 mixture of diastereoisomers that differ in the configuration of the pyranyl tertiary methyl group. The group of Christmann successfully synthesized (±)-peniprequinolone, (±)-aflaquinolones E and F, (±)-6-deoxyaflaquinolone E, (±)-quinolinones A and B, and (±)-aniduquinolone C by developing a general method for the construction of N-glycolated 2-aminobenzophenone via aryne insertions into unsymmetrical imides in flow (Scheme c) …”