Chirality Transfer in Gold(I)-Catalysed Direct Allylic Etherifications of Unactivated Alcohols: Experimental and Computational Study
作者:Graeme Barker、David G. Johnson、Paul C. Young、Stuart A. Macgregor、Ai-Lan Lee
DOI:10.1002/chem.201501607
日期:2015.9.21
necessary to ensure efficient and general chirality transfer. Computationalstudies suggest that the efficiency of chirality transfer is linked to the aggregation of the alcohol nucleophile around the reactive π‐bound Au–allylic ether complex. With a single alcohol nucleophile, a high degree of chirality transfer is predicted. However, if three alcohols are present, alternative proton transfer chain mechanisms
Synthesis Studies on the Lomaiviticin A Aglycone Core: Development of a Divergent, Two-Directional Strategy
作者:Ken S. Feldman、Brandon R. Selfridge
DOI:10.1021/jo4005074
日期:2013.5.3
a two-directional, divergent approach featuring (1) a double Ireland Claisen rearrangement to establish key core bonds with correct relative stereochemistry and (2) a double olefinmetathesis reaction to deliver both cyclohexene rings of the target.
[2,3]-Wittig Rearrangement of Enantiomerically Enriched 3-Substituted 1-Propenyloxy-1-phenyl-2-propen-1-yl Carbanions: Effect of Heteroatoms and Conjugating Groups on Planarization of an α-Oxy-Benzylcarbanion through a Double Bond
Don't get trapped: The effect of conjugating electron‐withdrawing groups and α‐anion‐stabilizing heteroatom substituents on configurational stability of chiral carbanions through a double bond was examined on the basis of extent of chirality transfer in intramolecular trapping in [2,3]‐Wittig rearrangement of chiral 3‐substituted 1‐propenyloxy‐1‐phenyl‐2‐propen‐1‐yl carbanions (see scheme).
Enantioselective addition of (Z)- and (E)-alkenylzinc bromides to aldehydes: asymmetric synthesis of sec-allylalcohols
作者:Wolfgang Oppolzer、Rumen N. Radinov
DOI:10.1016/s0040-4039(00)93553-6
日期:1991.10
In situ prepared (Z)- and (E)-1-alkenylzinc bromides 5 were added to various aldehydes 1 in the presence of lithiated (+)-N-methylephedrine or (+)-2-(N,N-dimethylamino)-1,2-diphenylethanol to give sec. allyalcohols 7 in high optical purity with simple recovery of the chiral aminol 6.
Enantiospecific, Nickel-Catalyzed Cross-Couplings of Allylic Pivalates and Arylboroxines
作者:Harathi D. Srinivas、Qi Zhou、Mary P. Watson
DOI:10.1021/ol5016724
日期:2014.7.3
We have developed an enantiospecific, nickel-catalyzed cross-coupling of unsymmetric 1,3-disubstituted allylic pivalates with arylboroxines. The success of this reaction relies on the use of BnPPh2 as a supporting ligand for the nickel(0) catalyst and NaOMe as a base. This method shows excellent functional group tolerance and broad scope in both the allylic pivalate and arylboroxine, enabling the preparation of 1,3-diaryl allylic products in high yields with excellent levels of regioselectivity and stereochemical fidelity.