Enantioselective, Catalytic One‐Pot Synthesis of
<i>γ</i>
‐Butyrolactone‐Based Fragrances
作者:Ceyda Kumru、Thomas Classen、Jörg Pietruszka
DOI:10.1002/cctc.201801040
日期:2018.11.7
Herein the preparative (1 g scale), stereoselective syntheses of various alkyl‐substituted γ‐butyrolactone fragrances 1 is described. The α,β‐unsaturated γ‐keto esters 2 as starting materials were synthesized by a Horner‐Wadsworth‐Emmons reaction and are further reduced by an ene reductase and alcohol dehydrogenase in a one‐pot enzyme cascade to nine desired γ‐butyrolactones 1, among them whisky (1 c)
Catalytic Enantioselective Fluorination and Amination of β-Keto Phosphonates Catalyzed by Chiral Palladium Complexes
作者:Sung Min Kim、Hye Ran Kim、Dae Young Kim
DOI:10.1021/ol050413a
日期:2005.6.1
[reaction: see text] The catalytic enantioselective fluorination and amination of beta-keto phosphonates catalyzed by chiral palladiumcomplexes is described. Treatment of beta-keto phosphonates with N-fluorobenzenesulfonimide (NFSI) as electrophilic fluorinating reagent and diethyl azodicarboxylate (DEAD) as electrophilic amination reagent under mild reaction conditions afforded the corresponding alpha-substituted
Asymmetric Synthesis of Tertiary α-Hydroxy Phosphonic Acid Derivatives under Aerobic Oxidation Conditions
作者:Biplab Maji、Hisashi Yamamoto
DOI:10.1055/s-0034-1380290
日期:——
The copper-catalyzed asymmetric α-hydroxylation of β-ketophosphonates, using in situ generated nitrosocarbonyl compounds as electrophilic source of oxygen, is reported. The reaction mergesaerobicoxidation and Lewis acid catalysis. α-Aminoxy-β-ketophosphonates were synthesized in high yields (up to 97% yield) and high enantioselectivities (up to >99% ee).
synthesized. Stereoselective assembly of C16, 17, 22, and an extra C21 stereocenter was achieved by two-directional Brown’s asymmetric allyl boration. Group selective PMP acetal formation and oxidative cleavage of vinyl group facilitated the differentiation of the ends of a two-directionally synthesized chain.
Copper-Catalyzed Asymmetric Synthesis of Tertiary α-Hydroxy Phosphonic Acid Derivatives with In Situ Generated Nitrosocarbonyl Compounds as the Oxygen Source
作者:Biplab Maji、Hisashi Yamamoto
DOI:10.1002/anie.201408893
日期:2014.12.22
α‐Hydroxy phosphonic acids and their derivatives are highly bioactive structural motifs. It is now reported that these compounds can be accessed through the copper‐catalyzed direct α‐oxidation of β‐ketophosphonates using in situ generated nitrosocarbonyl compounds as an electrophilic oxygen source. These reactions proceeded in high yields (up to 95 %) and enantioselectivities (up to >99 % ee) for both