Stereoselective Synthesis of Skipped Polyols by Substrate-Directed Asymmetric Induction
摘要:
A series of C-2- or sigma-symmetric oligo-1,3-dioxanylmethanes, 2-5, have been prepared using a bidirectional approach. In bidirectional syntheses of meso compounds, only substrate-based asymmetric induction could be applied. 1,3-Asymmetric induction in Mukaiyama-aldol additions, 1,5-asymmetric induction in enol-borinate aldol reactions, and 1,3-anti-selective reduction of aldols turned out to be reliable tools in the preparation of compounds 3-5.
Short eight-steps total synthesis of racemic asteriscunolide C
作者:Rodney A. Fernandes、Vijay P. Chavan、Arpita Panja
DOI:10.1080/00397911.2017.1365907
日期:2017.11.17
ABSTRACT A concise total synthesis of racemic asteriscunolide C in eight steps has been described starting from neopentane diol involving an efficient Yamaguchi esterification using an aldehyde-acid, intramolecular Horner–Wittig–Emmons olefination, and a late stage ring-closing metathesis to construct the strained 11-membered ring with one Z- and two E-double bonds. GRAPHICAL ABSTRACT
The Preparation and Utility of Bis(sulfinyl)imidoamidine Ligands for the Copper-Catalyzed Diels−Alder Reaction
作者:Timothy D. Owens、Andrew J. Souers、Jonathan A. Ellman
DOI:10.1021/jo020524c
日期:2003.1.1
The design and preparation of a novel class of ligands based on the sulfinyl imine functionality is described. In particular, an efficient and modular synthesis of bis(sulfinyl)imidoamidine (siam) ligands is reported. The versatility of the synthetic sequence is demonstrated by the preparation of various analogues to explore the effect of substitution about the ligand framework on catalytic activity
Synthesis and Character of New Bis- (isoxazoline) Ligands
作者:Hiroaki Sasai、Toshio Shinohara、Kazuhiko Wakita、Midori A. Arai、Takayoshi Arai
DOI:10.3987/com-02-s57
日期:——
Synthesis of two kinds of newbis(isoxazoline) ligand, achiral 2,2'-bis(isoxazolinyl)propane and (R)-2,2'-bis(isoxazolinyl)-1,1'-binaphthyl bearing an axial chirality is described. Both of the bis(isoxazoline) ligands accelerated the Pd(II)-catalyzed Wacker-typecyclization of alkenyl alcohol. The isoxazoline ligands were found to be essential to promote the cyclization.
Stereoselective synthesis of a series of 1,3-dioxan-4-ylmethanes 1−9 has been achieved by use of solely substrate-based asymmetric induction. The simple C2-symmetric bis(dioxanyl)methane 1 has a greater than 99% conformational preference at the two inter-ring bonds for the conformation 1a. The homologous structures 3−9 contain up to five dioxanylmethane units, maintaining a high conformational preference
Construction of the tetrahydrofuran ring part of polycavernoside A, which has been isolated as one of toxic principles from the red alga Polycavernosa tsudai, is described starting from 2,2-dimethylpropane-1,3-diol. The synthesis involves the Sharpless epoxidation and the Evans procedure for introduction of three chiral centers.