Octalactin A, an antitumor agent containing an eight-membered lactone moiety, has been stereoselectively prepared by means of enantioselective aldol reactions of selected silyl enolates with achiral aldehydes, promoted by a chiral Sn(II) complex. The medium-sized lactone part was effectively constructed by way of a new and rapid mixed-anhydride lactonization using 2-methyl-6-nitrobenzoic anhydride
Total synthesis of the polyene macrolide antibiotic roxaticin. I. Synthesis of the polyol fragment of roxaticin using a four-carbon chain extension strategy
The C11–C26 polyol fragment of roxaticin containing eight chiral centers has been prepared in a reiterative manner using coupling reactions of chiral dithianes and epoxides followed by stereoselective reduction.
Spirastrellolide E: synthesis of an advanced C(1)–C(24) southern hemisphere
作者:Alexander Sokolsky、Xiaozhao Wang、Amos B. Smith
DOI:10.1016/j.tetlet.2014.12.026
日期:2015.6
The synthesis of a C(1)–C(24) advanced southern hemisphere fragment towards the totalsynthesis of spirastrellolide E has been achieved. Highlights of the route include a highly convergent Type I Anion Relay Chemistry (ARC) tactic for fragment assembly, in conjunction with a directed, regioselective gold-catalyzed alkyne functionalization to generate the central unsaturated [6,6]-spiroketal.
Diarylprolinol‐Mediated Asymmetric Direct Cross‐Aldol Reaction of α,β‐Unsaturated Aldehyde as an Electrophilic Aldehyde
作者:Yujiro Hayashi、Kaito Nagai、Shigenobu Umemiya
DOI:10.1002/asia.201901236
日期:2019.12.2
The diarylprolinol-mediated asymmetric direct cross-aldol reaction of α,β-unsaturated aldehyde as an electrophilic aldehyde was developed. The reaction becomes accelerated by an acid when a carbonyl group is introduced at the γ-position of the α,β-unsaturated aldehyde. Synthetically useful γ,δ-unsaturated β-hydroxy aldehydes were obtained with high anti-selectivity and excellent enantioselectivity