Development of a C–C Bond Cleavage/Vinylation/Mizoroki–Heck Cascade Reaction: Application to the Total Synthesis of 14- and 15-Hydroxypatchoulol

Abstract

A C−C bond cleavage/vinylation/Mizoroki−Heck cascade reaction has been developed to provide access to densely functionalized bicyclo[2.2.2]octane frameworks. The sequence proceeds through the coupling of dihydroxylated pinene derivatives, prepared from carvone, with gem-dichloroalkenes. The method was applied to 12-step total syntheses of both 14-and 15hydroxypatchoulol, which provided unambiguous support for the structure of the natural products and corrects a misassignment in the isolation report.

Pd@l-asparagine–EDTA–chitosan: a highly effective and reusable bio-based and biodegradable catalyst for the Heck cross-coupling reaction under mild conditions

“…In the FTIR spectra, the observed bands at 3400 -3600 are attributed to the hydroxyl and amine groups, and the vibration double bands of C=O groups in EDTA dianhydride is stand in 1810 and 1760, respectively, which is displaced by amidic and acidic groups at 1675 cm −1 and 1733 cm −1 . The SP 3 C-H bands are shown at 2900 -3000 cm −1 and peaks at 1200 -1400 cm −1 are assigned to the bending of −NH groups. The C-O stretching band is located at about 1100 cm −1 .…”

“…Among different organic transformations, Heck crosscoupling reaction (HCR), also known as Mizoroki-Heck reaction, [1][2][3][4][5][6] has received significant interest due to its ability to form C-C bond formation in recent years. Indeed, these reactions have emerged as an efficient replacement, working under mild conditions, for Grignard reagents.…”

Practical and General Alcohol Deoxygenation Protocol

“…Despite the drawbacks of trialkyl tin reagents, the limitations of all alternative methods still regularly force the use of tin-based deoxygenation protocols, from academic settings to large-scale industrial processes. [41][42][43][44][45][46][47] Overall, introduction of a general, nontoxic, and practical method to deoxygenate alcohols would enable broader implementation of alcohol deletion approaches in synthesis.…”

“…While effective in some cases, these alternative methods suffer the synthetic limitations endemic to standard substitution chemistry; S N 1 requires readily ionizable alcohols and S N 2 proceeds only with unhindered alcohols. Despite the drawbacks of trialkyl tin reagents, the limitations of all alternative methods still regularly force the use of tin‐based deoxygenation protocols, from academic settings to large‐scale industrial processes [41–47] . Overall, introduction of a general, nontoxic, and practical method to deoxygenate alcohols would enable broader implementation of alcohol deletion approaches in synthesis.…”

Synthesis and Characterization of Post-β-Carbon-Elimination Organopalladium Complexes

“…bond decomposes into a π-bond-containing neutral ligand and a new anionic M–C′ complex with concomitant X–C′ bond cleavage (shown for the X = alkyl case in Scheme A) . β-Carbon elimination brings about a unique skeletal reorganization and as such plays an important role in organometallic polymerization, small-molecule catalysis, − and natural products synthesis, , with a growing number of recently published creative applications . In particular, ring-opening β-carbon elimination of highly strained molecules, such as cyclopropane/butane or norbornene, is a prevalent strategy to obtain linear compounds by employing strain-release as a thermodynamic driving force to overcome the high barrier of the β-carbon elimination step. ,, …”