diastereoselective. The allylation of benzaldehyde by 1-chlorobut-2-ene in 1,3-dimethylimidazolidin-2-one (DMI) does not occur with tin(II) chloride or bromide but does proceed with tin(II) iodide and exhibits gamma-syn selectivity which is unusual for a Barbier-type carbonylallylation. In the carbonylallylation by 1-chlorobut-2-ene with any tin(II) halide, the addition of tetrabutylammoniumiodide (TBAI) accelerates
Highly Regio- and Diastereoselective Tethered Aza-Wacker Cyclizations of Alkenyl Phosphoramidates
作者:Anand H. Shinde、Annu Anna Thomas、Joel T. Mague、Shyam Sathyamoorthi
DOI:10.1021/acs.joc.1c01483
日期:2021.11.5
We present highlydiastereoselective tethered aza-Wacker cyclization reactions of alkenyl phosphoramidates. “Arming” the phosphoramidate tether with 5-chloro-8-quinolinol was essential to achieving >20:1 diastereoselectivity in these reactions. The substrate scope with respect to alkenyl alcohols and phosphoramidate tether was extensively explored. The scalability of the oxidative cyclization was demonstrated
New and Stereoselective Synthesis of 1,4-Disubstituted Buten-4-ols (Homoallylic Alcohol α-Adducts) from the Corresponding γ-Isomers (3,4-Disubstituted Buten-4-ols) via an Acid-Catalyzed Allyl-Transfer Reaction with Aldehydes
from aldehydes via the usual reaction with common allylic metals 1, were converted to the corresponding α-adducts 6 by an acid-catalyzed allyl-transfer reaction. In the allyl-transfer reaction, anti- and syn-γ-adducts 3 gave E- and Z-α-adducts 6, respectively, and the optical purity of the γ-adducts 3 was transferred to the α-adducts 6 with >98%ee. This suggests that the allyl-transfer reaction proceeds
The First Example of Enantioselective Allyl Transfer from a Linear Homoallylic Alcohol to an Aldehyde
作者:Teck-Peng Loh、Chi-Lik Ken Lee、Kui-Thong Tan
DOI:10.1021/ol0263999
日期:2002.8.1
see text] The first example of enantioselective linear homoallylic alcohol transfer reaction was revealed. In all cases, the whole rearrangement is thermodynamically favorable and a steric effect is the drivingforce of this reaction. The preservation of the stereocenter and olefin geometry together with the isolation of gamma-adduct homoallylic alcohols in one isomeric form have warranted the proposed
Linear alpha homoallylic alcohol adducts were obtained with high regioselectivities in moderate to good yields using allylic indium reagents in the presence of 10 M water. The exceptionally high regioselectivities observed were neither steric nor electronic in origin from the results presented in this paper. (C) 2001 Elsevier Science Ltd. All rights reserved.