Isolable and Readily Handled Halophosphonium Pre-reagents for Hydro- and Deuteriohalogenation
作者:Florian T. Schevenels、Minxing Shen、Scott A. Snyder
DOI:10.1021/jacs.6b12653
日期:2017.5.10
and acid-sensitive moieties, particularly polyenes prone to cyclization. The process is also challenging when conducted on a small scale, and moreover, methods for the addition of their deuterated counterparts typically require special techniques, especially when control of stoichiometry is required. Herein is described a readily synthesized and handled reagent class which can accomplish the controlled
boron-mediated asymmetric Evans aldol reactions. Screening experiments of chiral N-acylated oxazolidinones 7, which are conveniently accessible from 5-methyl-5-hexenoic acid and Evans oxazolidinone auxiliaries, with various boron triflates and terpenoid neral (Z)-6a as aldehyde component, provided conditions in which highly selective formation of syn-aldol adduct 5a occurred and competing C=C double bond isomerization
Synthesis of Arieianal, a Prenylated Benzoic Acid from <i>Piper </i><i>a</i><i>rieianum</i>
作者:Sina I. Odejinmi、David F. Wiemer
DOI:10.1021/np050237e
日期:2005.9.1
for selective displacement of an allylic bromide in the presence of an allylicacetate and a stereoselective Horner-Wadsworth-Emmons condensation to afford the desired E olefin of the isoprenoid side chain. After the diterpenoid chain was joined to the aromatic ring, use of sodium metal in hot sBuOH allowed selectivecleavage of two benzyl ether protecting groups, and a sequence of oxidations gave
First enantioselective total synthesis of (natural) (+)-11,12-epoxy-11,12-dihydrocembrene-C and (−)-7,8-epoxy-7,8-dihydrocembrene-C
作者:Zuosheng Liu、Weidong Z. Li、Lizeng Peng、Ying Li、Yulin Li
DOI:10.1039/b007239g
日期:——
enantioselective totalsyntheses of (+)-11,12-epoxy-11,12-dihydrocembrene-C 1 and (−)-7,8-epoxy-7,8-dihydrocembrene-C 2, two naturally occurring cembranoxides isolated from tropical marine soft corals, are achieved via a generalapproach by employing an intramolecular McMurry coupling and Sharpless asymmetric epoxidation as key steps from readily available starting materials. The syntheses presented here
Strategies for the Total Synthesis of Diverse Bromo-Chamigrenes
作者:Minxing Shen、Manuel Kretschmer、Zachary G. Brill、Scott A. Snyder
DOI:10.1021/acs.orglett.6b02478
日期:2016.10.7
their unique structures, synthetic efforts toward this collection have been modest. Herein, we outline two strategies to generate their skeletons based on (1) a biomimetic bromonium-inducedpolyenecyclization using BDSB (Et2SBr·SbCl5Br) and (2) a Diels–Alder reaction which ultimately delivered four members of the class. In addition, X-ray crystallography reveals that one member has a structure in need