Regio- and Enantioselective Catalytic Monoepoxidation of Conjugated Dienes: Synthesis of Chiral Allylic <i>cis</i>-Epoxides

Ti­(IV)-salan <b>4</b> catalyzes the diastereo- and enantioselective monoepoxidation of conjugated dienes using 30% H₂O₂ at rt or below even in the presence of other olefins and adjacent stereocenters. Its enantiomer, <i>ent</i>-<b>4</b>, provides access to the opposite diastereomer or enantiomer. The resultant chiral allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The epoxidation is highly specific for <i>Z</i>-olefins. For 1-acyl­(silyl)­oxypenta-2,4-dienes, epoxidation of the distal olefin is generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes

Regio- and Stereoselective Monoepoxidation of Dienes using Methyltrioxorhenium: Synthesis of Allylic Epoxides

Methyltrioxorhenium (MTO) complexed with pyridine was shown to be a highly effective catalyst for the regioselective monoepoxidation of conjugated di- and trienes using 30% H₂O₂ at or below room temperature. The resultant allylic epoxides, and the triols derived from them, are versatile synthetic intermediates as well as substructures present in many bioactive natural products. The site of epoxidation was dependent upon olefin substitution, olefin geometry (<i>Z</i> vs <i>E</i>), and the presence of electron-withdrawing substituents on adjacent carbons. For 1-acyl­(silyl)­oxypenta-2,4-dienes, epoxidation of the distal olefin was generally favored in contrast to the adjacent regioselectivity characteristic of Sharpless, peracid, and other directed epoxidations of hydroxylated dienes

Additional file 1: Figure S1. of Between Lake Baikal and the Baltic Sea: genomic history of the gateway to Europe

Quality control process. (PDF 25 kb

Additional file 3: Table S1a. of Between Lake Baikal and the Baltic Sea: genomic history of the gateway to Europe

List of samples included in “Extended” dataset. Table S1b List of samples included in “Core” dataset. Table S1c List of samples included in “Ancient” dataset. Table S2 Results of ADMIXTURE for K = 9. Table S3 Results of ADMIXTURE for K = 6, 7, 8. Table S4 Results of f3 test. Table S5 Results of IBD sharing analysis in 1–3 cM and 4–10 cM bins. Table S6 Total amount of shared IBD between populations. Table S7 Standard residue of linear regression analysis of distance-IBD sharing. Table S8 Distance and shared IBD between pairs of populations. Table S9: Results of f3 outgroup test with ancient samples. (XLSX 482 kb