By Epoxide Ring Opening

Carbohydrate Chemistry, Volume 34 The Royal Society of Chemistry, 2003 

have been synthesized by alkylation at N-1 of the benzodiazepine, e.g. with a 5,6-anhydro-D-glucofuranose derivative as electrophile. The pyrimidine-substituted L-ascorbic acid derivative 6 of has been obtained by ring opening addition to a 5,6-epoxide. A related 4,5-unsaturated analogue was also reported.  

Reagents i, TmsC=CMgBr ii, BU4NF iii, Zn(N3)2, PhaP, Pr 02CN= NCOaPr  

Reagents i, NaNa, SiOa, MeCN ii, Na2Cr207, EtOH, H2O then 

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Entry 8 involves a migration initiated by epoxide ring opening. This reaction involves migration of a vinyl substituent. Entry 9 is a stereospecific migration of the aryl group. The DiBAlH both promotes the rearrangement and reduces the product aldehyde. 

Functional groups were selectively introduced at the C-2 position of isophorone by epoxide ring-opening by several nucleophiles with active methylene groups. Different behavior was observed depending on the reaction conditions and the nature of the nucleophilic agents [57]. The best experimental systems involved PTC or KF-alumina under solvent-free conditions and MW irradiation (Eq. 37 and Tab. 5.15). 

Carbocation formation is initiated by epoxide ring opening in squalene oxide, giving a tertiary carbocation, and this is transformed into the four-ring system of the protosteryl cation by a series of electrophilic addition reactions (see Box 8.3). 

The compound (70) by epoxide ring-opening with hydrogen fluoride, followed by photocatalysed addition of acetylene to the A16-bond and lithium aluminium hydride reduction, gave (71). Protection of the 1,2-diol system in (71) as the acetonide followed by oxidation, dehydration, and regeneration of the diol grouping produced... 

Reactions of epoxides with amines, azides, hydrazines, etc., formation of N-heterocycles by epoxide ring opening 04ZOR11. 

Oxaspiropentanes are classified as a unique class of cyclopropyl ethers. Two reaction courses are recognized as being associated with the reaction in the presence of lithium bases. Treatment of oxaspiropentanes with butyllithium leads to S 2-type epoxy ring opening, giving butyl-connected cyclopropanols. On the other hand, with lithium amide as base there is deprotonation at the epoxy carbon followed by epoxide ring opening. The latter reaction offers a useful synthesis of 1-vinylcyclopropanols. ... 

Cyclization initiation can also be achieved by epoxide ring opening but using this procedure mixtures of products are found28-34. Mixtures of constitutional isomers are observed when naturally occurring caryophyllene or isocaryophyllene are treated with mineral acids 35. 

Although hydroxylation of phenylalanine to tyrosine looks like a typical electrophilic aromatic substitution, scientists at the U.S. National Institutes of Health discovered that the biochemical pathway combines epoxidation of the benzene ring followed by epoxide ring-opening with rearrangement. This rearrangement, which is the biochemical analog of the pinacol-type reactions described earlier, is known as the NIH shift. ... 

Triphati BP, Kumar M, Shahi VK (2010) Organic-inorganic hybrid alkaline membranes by epoxide ring opening for direct methanol fuel cell applications. J Membr Sci 230 90-101... 

The same group reported the synthesis of 2,6-dimethyl-2-homoprenylchroman-3-ol via a Payne rearrangement of the epoxide 7 followed by epoxide ring opening reaction. 

The main features of the mechanism of the anionic polymerisation of PPO have been well established by C-NMR [28, 29]. Propagation proceeds principally by epoxide ring opening via anionic attack at the secondary ring carbon, giving regular head-to-tail monomer enchainment ... 

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