A mild access to chiral syn 1,2-diaryl glycols by stereoselective ring opening of ortho substituted trans 2,3-diaryl-oxiranes using Amberlyst 15 in H2O/THF system
摘要:
Amberlyst 15 was an efficient and green catalyst for the reaction of 2,3-diaryloxiranes with H2O in organic co-solvent to prepare glycols in high yield. Ortho substituted trans 2,3-diaryloxiranes afforded the corresponding syn glycols stereo- and enantiospecifically. Stereoselectivity appeared related to the coordination ability of the substituents, irrespective of their electronic properties. Indeed o-OCH3 and o-OBn substituted syn glycols were obtained in high stereochemical ratios (6/1 and 10/1, respectively), and o-OTIPS and o-NO2 substituted ones were obtained as exclusive products, with the same ee of the parent epoxides. (C) 2015 Elsevier Ltd. All rights reserved.
symmetrical trans-stilbene oxide, the syn- versus anti-bromohydrins ratio ranged between 88/12 and 30/70, by varying the reaction temperature from 20 to −30 °C. In the case of nonsymmetrical para-substituted trans-2,3-diaryloxiranes, the regioselectivity is determined by electroniceffects. If one phenyl bears a strong electron-withdrawing group (as NO2 or CF3), the nucleophilic attack is totally on the
Arynes are utilized in the syntheses of 1,2‐dihydroquinolines, epoxides, and phenolic ethers involving Diels‐Alder, Johnson‐Corey‐Chaykovsky, and Claisen‐type rearrangement reactions, respectively, through three different domino processes
New Aniline-Containing Amino Alcohols from <i>trans</i>-(<i>R</i>,<i>R</i>)-2-(2-Nitrophenyl)-3-phenyloxirane as Useful Intermediates for the Synthesis of Chiral Ligands, Bases, and Benzoxazine Nucleus
作者:Arlette Solladié-Cavallo、Paolo Lupattelli、Carlo Bonini、Valeria Ostuni、Nadia Di Blasio
DOI:10.1021/jo0617969
日期:2006.12.1
New enantiopure aniline-containing amino alcohols are directly derived from trans-(R,R)-2-(2-nitrophenyl)-3-phenyloxirane, by alternative regioselective double reductions. Subsequent selective alkylation procedures and derivatizations provide a rapid and high-yielding access to different chiral ligands, bases, and benzoxazines, without loss of optical purity.
ALLEN, D. G.;WILD, S. B., ORGANOMETALLICS, 1983, 2, N 3, 394-399