Preparation of Boc-Protected Cinnamyl-Type Alcohols: A Comparison of the Suzuki-Miyaura Coupling, Cross-Metathesis, and Horner-Wadsworth-Emmons Approaches and Their Merit in Parallel Synthesis
作者:Jan Štambaský、Andrei V. Malkov、Pavel Kočovský
DOI:10.1135/cccc20080705
日期:——
Three synthetic strategies for the construction of tert-butyl (E)-3-arylprop-2-en-1-ol carbonates are described. Complementary approaches employing Suzuki-Miyaura coupling and cross-metathesis reaction gave moderate yields of the title compounds in one-step, both methods are suitable for high-throughput and parallel chemistry. A detailed investigation into the Suzuki-Miyaura coupling reaction is provided along with the studies on the synthesis of pinacolyl 1-(tert-butyloxycarbonyl)propenol-3-ylboronate, the key building block. Conventional synthesis of the title compounds via the Horner-Wadsworth-Emmons reaction as a key step in a three-step-one-purification protocol was optimized and the results are compared with those of the latter reactions.
Herein we report the firsttotalsynthesis of alkaloid caulophyllumine B in 14 steps by an iterative olefincross-metathesis strategy from l-glutamic acid.
4-tetrafluorocyclobutene with electronically rich alkenes as butyl vinyl ether or electron donor group substitutedstyrenes gave a library of non-symmetrically substituted tetrafluorodienes, which could be further transformed by cross metathesis with styrenes to fluorinated internal dienes or by oxidation and cyclization to tetrafluorohexopyranoses.
Alkene radical ions constitute an integral and unique class of reactive intermediates for the synthesis of valuable compounds because they have both unpaired spins and charge. However, relatively few synthetic applications of alkene radical anions have emerged due to a dearth of generally applicable and mild radical aniongeneration approaches. Precise control over the chemo- and stereoselectivity