38614-13-0

Basic information

• Product Name: (2E)-2-ethylidenetetrahydrofuran
• Synonyms: endo-2-Ethylidenetetrahydrofuran; exo-2-Ethylidenetetrahydrofuran
• CAS NO: 38614-13-0
• Molecular Formula: C₆H₁₀O
• Molecular Weight: 98.143
• Mol File: 38614-13-0.mol

Chemical Properties

• Boiling Point: 129.3°C at 760 mmHg
• Flash Point: 21.8°C
• Density: 1.012g/cm³
• Vapor Pressure: 12.5mmHg at 25°C
• Refractive Index: 1.55
• CAS DataBase Reference: (2E)-2-ethylidenetetrahydrofuran(CAS DataBase Reference)
• NIST Chemistry Reference: (2E)-2-ethylidenetetrahydrofuran(38614-13-0)
• EPA Substance Registry System: (2E)-2-ethylidenetetrahydrofuran(38614-13-0)

Safety Data

• Hazardous Substances Data: 38614-13-0(Hazardous Substances Data)

Upstream product

• 928-93-8 4-hexyn-1-ol 
• 928-90-5 5-hexyl-1-ol 

Relevant articles and documents

Alkaline earth catalysis of alkynyl alcohol hydroalkoxylation/cyclization

Heavier alkaline earth bis(trimethylsilyl)amides [Ae{N(SiMe 3)2}2]2 (Ae = Ca, Sr, Ba) are shown to act as effective precatalysts for the regioselective intramolecular hydroalkoxylation/cyclization of a wide range of alkynyl and allenyl alcohols. In the majority of cases, cyclization of alkynyl alcohols produces mixtures of the possible endo- and exocyclic enol ether products, rationalized as a consequence of alkynylalkoxide isomerization to the corresponding allene derivatives. Cyclization rates for terminal alkynyl alcohols were found to be significantly higher than for substrates bearing internal alkynyl substituents, while the efficacy of cyclization was in general found to be determined by a combination of stereoelectronic influences and the thermochemical viability of the specific alkaline earth metal catalysis, which we suggest is determined by the individual M-O bond strengths. Kinetic studies have provided a rate law pertaining to a pronounced catalyst inhibition with increasing [substrate], indicating that turnover-limiting insertion of C-C unsaturation into the M-O bond requires the dissociation of substrate molecules away from the Lewis acidic alkaline earth center.

Intramolecular hydroalkoxylation/cyclization of alkynyl alcohols mediated by lanthanide catalysts. Scope and reaction mechanism

Lanthanide-organic complexes of the general type Ln[N(SiMe 3)2]3 (Ln = La, Sm, Y, Lu) serve as effective precatalysts for the rapid, exoselective, and highly regioselective intramolecular hydroalkoxy- lation/cyclization of primary and secondary alkynyl alcohols to yield the corresponding exocyclic enol ethers. Conversions arehighly selective with products distinctly different from those generall y produced by conventional transition metal catalysts, and turnover frequencies as high as 52.8 h-1 at 25 °C are observed. The rates of terminal alkynl alcohol hydroalkoxylation/cyclization are significantly more rapid than those of internal alkynyl alcohols, arguing that steric demands dominate the cyclization transition state. The hydroalkoxylation/cyclization of internal alkynyl alcohols affords excellent E -selectivity. The hydroalkoxylation/ cyclization of the SiMe3-terminated internal alkynyl alcohols reveals interesting product profiles which include the desired exocyclic ether, a SiMe3-eliminatedexocyclic ether, and the SiMe3-O- functionalized substrate. The rate law for alkynyl alcohol hydroalkoxylation/ cyclization is first -order in [catalyst] and zero-order in [alkynyl alcohol], as observed inthe intramolecular hydroamination/cyclization of aminoalkenes, aminoalk ynes, and aminoallenes. An ROH/ROD kinetic isotope effect of 0.95(0.03) is observed for hydroalkoxy- lation/cyclization. These mechanistic data implicate turnover-limiting insertion of C-C unsaturation into the Ln-O bond, involving a highly organized transition state, with subsequent, rapid Ln-C protonolysis.