Alkyl metal asymmetric reduction. 11. The reaction of α,β-unsaturated ketones with β-branched trialkylaluminium compounds.
作者:Giampaolo Giacomelli、Anna Maria Caporusso、Luciano Lardicci
DOI:10.1016/s0040-4039(01)81987-0
日期:1981.1
The reduction of a series of α,β-unsaturated ketones has been studied under various experimental conditions, by using β-branched trialkylalanes. Asymmetric induction phenomena are observed when optically active trialkylalanes are used.
Rhodium-Catalyzed Allylic Substitution with an Acyl Anion Equivalent: Stereospecific Construction of Acyclic Quaternary Carbon Stereogenic Centers
作者:P. Andrew Evans、Samuel Oliver、Jungha Chae
DOI:10.1021/ja306602g
日期:2012.11.28
A highly regio- and stereospecific rhodium-catalyzed allylic alkylation of tertiary allylic alcohol derivatives with a cyanohydrin pronucleophile is described. This direct and operationally simple protocol provides a fundamentally novel approach toward the synthesis of α-quaternary substituted ketones and circumvents many of the inherent problems associated with conventional enolate alkylation reactions
The present invention relates to the use of specific organic compounds as flavor and fragrance material. Furthermore the invention relates to new specific organic compounds, as well as to flavor and fragrance formulations comprising at least one of the specific organic compounds.
Use of peelable film-forming organopolysiloxane compositions
申请人:Toray Silicone Company Limited
公开号:EP0094185A2
公开(公告)日:1983-11-16
Room temperature-storable, heat-curable organopolysiloxane compositions which comprise silicon-bonded vinyl radicals, silicon-bonded hydrogen atoms, a platinum-type compound and characterized by an unsaturated hydrocarbon compound of the conjugated ene-yne type provide a release surface for tacky substances when coated onto the surface of a base material and heated, even mildly. The release surface possesses a time- stable release ability, particularly for pressure sensitive adhesive bearing articles such as tapes and labels.
Process for preparing organosiloxanes having in the mol- cute at least one unit of the general formula
which R is C1-4 alkyl or a phenyl group, R' represents an aliphatic or aromatic group composed of carbon, hydrogen and optionally oxygen and having a valency of n + 1, Y represents )H or alkoxy, is 0, 1 or 2, is 0 or 1 and n is 1, 2 or 3. The process comprises reacting an organosiloxane having silicon- onded hydroxyalkyl or hydroxyaryl substituents with the appropriate acid chloride.
The organosiloxanes absorb ultra violet radiation and are seful as sunscreen agents.
Also claimed are certain novel siloxanes which can be ob- ained by the said process.