This method facilitates the construction of cis‐1,4‐silaketals (n=0, d.r.=20:1; see scheme), whereas the extension of this concept to higher alkenyl alcohols (n=1–4) results in a reversal of diastereoselectivity that favors formation of the trans isomer.doi:10.1002/anie.200250486...
Finally, reductive cleavage of the cobalt complex and hydrogenation of the double bonds afforded the target (+)-cis-lauthisan 72, αD25=+4.1(c 0.9, CHCl3). Sign in to download full-size image Scheme 8. The synthesis of polycyclic ethers with variable ring sizes can be conducted by two...
Scheme 3. Study of the ring closing enyne metathesis reaction. The RCEYM efficiency was further enhanced by prolonging the reaction time up to 72 h and adopting a ≃0.05 M starting concentration which reaches 0.01 M after slow addition of the catalyst. Moreover, we succeeded in re...
14.A process according to claim 1, wherein in the compounds of formulas (I) and (III):RAis —OSO2—R27, wherein R27is p-bromophenyl;R3is NH—C(O)—OR20, wherein R20is cyclopentyl;R4is H;D is a 5 atom all carbon chain containing one cis double bond at position 13,14; and ...
FIG. 3: Structures of non-limiting examples of suitable catalysts for a ring-closing metathesis reaction.FIG. 4: Scheme showing a non-limiting example of the three-step method to produce C11, C12, and C13 lactams.FIG. 5: Non-limiting example of step 1, amide formation of 9-decenoic acid...
describe a new approach to long-range asymmetric induction using the diastereoselective temporary silicon-tethered (TST) ring-closing-metathesis (RCM) reaction of mixed bisalkoxy silanes 1, derived from an allylic and prochiral alcohol, for the construction of cis-1,4-silaketals 2 (Scheme 1; n...
First, we carried out the model reaction at 60 °C by using the aminomethyl cyclopalladated complex-A as the catalyst, the undesired non-cyclic allenic 1,5-diamine 4aa was obtained in 20% yield (Scheme 3A-1), which indicated that the palladium-catalyzed aminomethylamination reaction of ...
em@geus.dk; Tel.: +45-91-33-38-62 Received: 31 July 2017; Accepted: 3 October 2017; Published: 24 October 2017 Abstract: This article addresses a research gap on the challenges—specifically risk and value—connected to realizing the potential for closing loops for rare earth elements (REE...