Enantio- and Diastereoselective Synthesis of <i>N</i>-Acetyl Dihydrotetrafibricin Methyl Ester
作者:Philippe Nuhant、William R. Roush
DOI:10.1021/ja401918r
日期:2013.4.10
methyl ester (34) is described. The synthesis features three enantioselective double allylborationreactions and an intramolecular hydrosilylation/Fleming-Tamao oxidation sequence to establish seven of the hydroxy-bearing stereocenters of 34. Especially noteworthy is the fragment-assembly double allyboration reaction of 2 and 7 using reagent 3, which provides the advanced intermediate 6 with >20:1 diastereoselectivity
Generation of Stereochemically Defined Tetrasubstituted Enolborinates by 1,4-Hydroboration of α,β-Unsaturated Morpholine Carboxamides with (Diisopinocampheyl)borane
作者:Christophe Allais、Andy S. Tsai、Philippe Nuhant、William R. Roush
DOI:10.1002/anie.201307302
日期:2013.12.2
fours: The title reaction with (Ipc)2BH provides tetrasubstitutedenolborinates which undergo aldol reactions with aldehydes to form products with all‐carbon quaternary centers with exceptional diastereo‐ and enantioselectivity. A change to the substitution pattern of the starting amide leads to either diastereomer of the α‐methyl‐α‐ethyl‐β‐hydroxy carboxamide (1 or 2).
Enantio‐ and Diastereoselective (Ipc)<sub>2</sub>BOTf‐Mediated Aldol Reactions of Morpholine Carboxamides
作者:Lee Pedzisa、Andrii Monastyrskyi、Camille D. Parker、William R. Roush
DOI:10.1002/hlca.202300126
日期:2023.12
Highly enantio- and diastereoselective (Ipc)2BOTf mediated aldolreactions of morpholine carboxamides are described. A wide variety of α-substituted N-acyl morpholine carboxamides were successfully employed, including α-bromo, α-chloro, α-vinyl and para-methoxyphenyl morpholine carboxamides which provided the corresponding aldol products in moderate to excellent yields, and generally with high enantio-
(Diisopinocampheyl)borane-Mediated Reductive Aldol Reactions of Acrylate Esters: Enantioselective Synthesis of <i>Anti</i>-Aldols
作者:Christophe Allais、Philippe Nuhant、William R. Roush
DOI:10.1021/ol401679g
日期:2013.8.2
The (diisopinocampheyl)borane promoted reductive aldol reaction of acrylate esters 4 is described. Isomerization of the kinetically formed Z(O)-enolborinate 5Z to the thermodynamic E(O)-enolborinate 5E via 1,3-boratropic shifts, followed by treatment with representative achiral aldehydes, leads to anti-alpha-methyl-beta-hydroxy esters 9 or 10 with excellent diastereo- (up to >= 20:1 dr) and enantioselectivity (up to 87% ee). The results of double asymmetric reactions of 5E with several chiral aldehydes are also presented.
10.15227/orgsyn.92.0038
作者:Abbott, Jason R.、Allais, Christophe、Roush, William R.