Synthesis of a Lactone Diastereomer of the Cembranolide Uprolide D
作者:James A. Marshall、Céline A. Griot、Harry R. Chobanian、William H. Myers
DOI:10.1021/ol101776e
日期:2010.10.1
A convergent stereoselective synthesis of a C1/C14 bis-epimer of uprolide D is described in which an intramolecular Barbier-type reaction was employed for macrocyclization with concomitant introduction of the C1 and C14 stereocenters of a fused α-methylene lactone ring through an anti-Felkin−Anh transition state. Unlike previous examples of allyl chromium additions, none of the Felkin−Anh derived adduct
Diastereoselective Synthesis of Highly Substituted Tetrahydrofurans by Pd-Catalyzed Tandem Oxidative Cyclization–Redox Relay Reactions Controlled by Intramolecular Hydrogen Bonding
作者:Joshua L. Brooks、Liping Xu、Olaf Wiest、Derek S. Tan
DOI:10.1021/acs.joc.6b02053
日期:2017.1.6
4-benzoquinone catalyst system coupled with introduction of a hydrogen-bond acceptor in the substrate enhances both diastereoselectivity and reactivity. Cyclization occurs with 5-exo Markovnikov regioselectivity. Mechanistic and computational studies support an anti-oxypalladation pathway in which intramolecular hydrogen bonding increases the nucleophilicity of the alcohol and enforces conformational constraints
Transannular Diels-Alder model studies on the total synthesis of chatancin. The furanophane approach. Part 1: Assembly of the acyclic substrates
作者:András Toró、Yuan Wang、Pierre Deslongchamps
DOI:10.1016/s0040-4039(99)00323-8
日期:1999.4
Synthesis of three generations of model substrates with advancing similarity to chatancin are presented. In the first two generations, an Ireland-Claisen based six-step sequence supplied the trans-dienophile to be connected by dithiane chemistry to furfurals. In the third generation, a homogeraniol based dienophile aldehyde was coupled with a dilithiated 3-furoic acid. Subsequently, all three generations