An empirically based relationship between overall complex stability (-DeltaG degrees ) and various possible component interactions is developed to probe the question of whether the A.T/U and G.C base-pairs exhibit enhanced stability relative to similarly hydrogen-bonded complexes. This phenomenological approach suggests ca. 2-2.5 kcal mol-1 in additional stability for A.T owing to a group inter...

The [2 + 2] cycloaddition of monosubstituted acetylenes to ketene has been studied by ab initio(G2(MP2,SVP) and DFT (B3LYP/6-31Gd)) methods. The activation barrier decreases with increasing electron-donating ability of the acetylene substituent, and it can be roughly correlated with the energy of the acetylene HOMO. The addition to the C[double bond, length as m-dash]C bond of ketene (giving cy...

A convenient base-mediated strategy to synthesize 3-aryol-4-methyl (or benzyl)-2-methylthio furans 2 (trisubstituted furans) has been developed through the domino coupling/annulations between available α-oxo ketene dithioacetals 1 and propargyl alcohols. In this strategy, these types of bases play an important role in driving the domino coupling reaction of propargyl alcohols and further intram...

Abstract. A compound was observed using airborne proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) measurements in the emission plumes from Daesan petrochemical facility South Korea. The detected at m/z 43.018 on PTR-TOF-MS and tentatively identified as ketene, a rarely measured reactive volatile organic (VOC). Estimated ketene mixing ratios high ∼ 50 ppb (parts per billion...

An examination into the derivatization of various natural products using newly developed alpha-fluorination methodology is disclosed. An activated ketene enolate, generated from an acid chloride, is allowed to react with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product produces biologically relevant alpha-fluorinated carbonyl derivatives of sel...