Divergent Enantioselective Synthesis of (−)-Galanthamine and (−)-Morphine
作者:Barry M. Trost、Weiping Tang、F. Dean Toste
DOI:10.1021/ja054449+
日期:2005.10.1
tricyclic intermediate is available in six steps from 2-bromovanillin and the monoester of methyl 6-hydroxycyclohexene-1-carboxylate. This intermediate requires only two steps to convert to (-)-galanthamine. Using a Heck vinylation, we found that the fourth ring of codeine/morphine could be formed. The final ring formation involves a novel visible light-promoted hydroamination. Thus, six steps are required
Development of Aliphatic Alcohols as Nucleophiles for Palladium-Catalyzed DYKAT Reactions: Total Synthesis of (+)-Hippospongic Acid A
作者:Barry M. Trost、Michelle R. Machacek、Hong C. Tsui
DOI:10.1021/ja050340q
日期:2005.5.1
The ability to use aliphatic alcohols as competent nucleophiles in the palladium-catalyzed dynamic kinetic asymmetric transformation of Baylis-Hillman adducts is explored. High yield and enantioselectivity is obtained for both the kinetic transformation and dynamic kinetic transformation. The absolute stereochemistry of the products is used to explore the reactive conformation of 2-substituted pi-allyl
The first enantioselective total synthesis of tangutorine has been achieved, wherein a Pd-catalyzed asymmetric allylic amination using a chiral diaminophosphine oxide (DIAPHOX) preligand was the key step.
Asymmetric Synthesis of (−)-Anatoxin-a via an Asymmetric Cyclization Using a New Ligand for Pd-Catalyzed Alkylations
作者:Barry M. Trost、Johan D. Oslob
DOI:10.1021/ja983617d
日期:1999.4.1
trans-1,2-diaminocyclohexane and 2-diphenylphosphinobenzoic acid effect asymmetric alkylations with an allyl substrate bearing an electron-withdrawing group. On the other hand, a new type of ligand wherein the diamine is derivatized with both 2-diphenylphosphinobenzoic acid and 2-picolinic acid was required to effect asymmetriccyclization to form the 9-azabicyclo[4.2.1]non-2-ene system. A total synthesis
A Pd-catalyzedasymmetricallylicalkylation of 2-substituted cycloalkenyl carbonates using a chiral diaminophosphine oxide is described. Asymmetricallylic substitution of various cyclicsubstrates proceeded using 5 mol % of Pd catalyst, 10 mol % of (S,RP)-Ph-DIAPHOX 1, 10 mol % of LiOAc, and N,O-bis(trimethylsilyl)acetamide (BSA), to afford the corresponding products in excellent yields with up to