A Chiral Pentenolide-Based Unified Strategy toward Dihydrocorynantheal, Dihydrocorynantheol, Protoemetine, Protoemetinol, and Yohimbane
摘要:
An organocatalytic cross-aldol reaction of formaldehyde (formalin) with alkyl aldehydes, followed by the Z-selective Horner-Wadsworth-Emmons (HWE) reaction and immediate lactonization, afforded gamma-alkylated pentenolides in good overall yields and excellent enantioselectivities. Based on this scalable sequence, five quinolizidine alkaloids were synthesized in a unified and concise manner. The development of an in situ activation of a tertiary amide to improve the efficiency of the Bischler-Napieraiski (B-N) reaction was also noteworthy due to the generality to sensitive substrates for a variety of target molecules.
the total synthesis of (±)‐gephyrotoxin has been developed. The key to success was the utilization of N‐methoxyamides, which enabled the direct coupling of the amide with an aldehyde and selective reductive nucleophilic addition to the amide in the presence of a variety of sensitive and electrophilic functional groups, such as a methyl ester. This chemoselective approach minimized the use of protecting‐group
Total syntheses of melinonine-E and strychnoxanthine: Evolution of the synthetic strategy enabled by novel method development
作者:Jisheng Luo、Changmin Xie、Yuping Zhang、Sha-Hua Huang、Lili Zhu、Ran Hong
DOI:10.1016/j.tet.2018.08.015
日期:2018.10
In this full account, the evolution of a syntheticstrategy was detailed from a nitroso-ene cyclization to an aza-Wacker reaction for ring construction in the syntheses of melinonine-E and strychnoxanthine. The aza-Wacker cyclization to form the bridged ring was successfully developed and applied in the first asymmetric syntheses of melinonine-E and strychnoxanthine in 5–6 steps from a readily available
Stereoselective Synthesis of the C1–C9 and C11–C25 Fragments of Amphidinolides C, C2, C3, and F
作者:Daniel C. Akwaboah、Dimao Wu、Craig J. Forsyth
DOI:10.1021/acs.orglett.7b00217
日期:2017.3.3
An efficient synthesis of the C1–C9 and the C11–C25 fragments of amphidinolides C, C2, C3, and F from a common intermediate is reported. The construction of the C1–C9 fragment involves an intramolecular hetero-Michael cyclization to form the 3,5-disubstituted trans-tetrahydrofuran moiety. The approach to prepare the C11–C25 fragment utilizes a highly stereoselective aerobic cobalt-catalyzed alkenol
A Straightforward, Purification-Free Procedure for the Synthesis of Ando and Still–Gennari Type Phosphonates
作者:Ignacy Janicki、Piotr Kiełbasiński
DOI:10.1055/a-1628-7586
日期:2022.1
Z-Selective Still–Gennari and Ando modifications of the typically E-selective Horner–Wadsworth–Emmons reaction are highly valuable synthetic tools in organic chemistry. These procedures are based on application of bis(2,2,2-trifluoroethyl) phosphonates or diaryl phosphonates, respectively, for the olefination of carbonyl groups. In our research, we present an improved, straightforward, purification-free
The Use of COP-OAc in the Catalyst-Controlled Syntheses of 1,3-Polyols
作者:Stefan Kirsch、Philipp Klahn、Helge Menz
DOI:10.1055/s-0031-1289574
日期:2011.11
Elongation via RCM (Cycle A) 2.2 TotalSynthesis of Rugulactone 2.3 Chain Elongation via Ando Olefination (Cycle B) and Total Syntheses of Polyrhacitides A and B 2.4 Useful Variants 3 Conclusions polyols - palladium - catalysis - natural products - esters