The stereocontrolled construction of the adjacent tertiary carbons is important in the synthesis of various natural products. By conducting the Michael addition of ester and amide enolates to α, β-unsaturated esters under appropriate reaction conditions, glutaric acid derivatives with definite relative and absolute configuration are prepared. In combination with intramolecular carbon-carbon bond formation, the process is extended to the stereoselective formation of extracyclic chiral centers, and successfully applied to the synthesis of (+) -dehydroiridodiol. Several other approaches to the stereoselective synthesis of adjacent tertiary carbons are also included.
4H-Cyclopenta [def] phenanthrene (1) is an interesting polycyclic aromatic hydrocarbon having active methylene group. Recently, 1 attracts attention in the field of environmental chemistry because some of the derivatives show mutagenic activity. This paper deals with the syntheses and reactivities of 1 and related compounds, which are classified into reaction on the active methylene, electrophilic substitution, and reaction of the fairly localized 8-9 double bond, from the viewpoint of 1) occurrence and bioactivity, spectral characterization ; 2) synthesis of frame ; 3) reaction at active methylene ; 4) electrophilic substitution ; 5) oxidation and reduction, and the related reactions.
Recent studies on chromotropism such as photochromism, thermochromism, piezochromism, and electrochromism of organic compounds are described. Main topics are as follows : 1. Development of heterocyclic fulgids which are thermally stable photochromic compounds free from photochemical side reactions, and suited for use in information storages. 2. Finding of photochromism and thermochromism of viologens by an electron-transfer reduction-oxidation mechanism, similar to that of electrochromism of viologen family. 3. Survey of piezochromic materials which exhibit change of color on grinding, or pressing and revert to origingl color on heating or exposed to the vapor of organic solvents.
Organic plasma chemistry is the valuable and novel field of preparative chemistry in which a variety of active species generated by glow discharge such as free radical, electron, ion, excited molecule, and photon are utilized. The reactions include cyclization, dehydrogenation, isomerization, elimination, substitution, reduction, polymerization, and others. During the last decade a number of preparative methods have been reported and some of them were summarized in this brief article. In addition, plasma reduction and plasma-initiated polymerzation, in both cases energetic electrons in the gas phase transfer to liquid phase and attack subsequently to the molecules, will be introduced. Plasma polymerization is now becoming a common method to give organic thin films. Their structures, properties, and applications will also be described.
Synthetic utility of methoxy (phenylthio) methane (1) as an effective C1 homologation reagent is described. The adducts of 1 with electrophiles can be converted to a variety of compounds in a quite selective manner under mild reaction conditions. The unique modifications of these adducts are attributable to activation of the moieties substituted unsymmetrically by different functional groups.