Les amines et lessulfes de β-malonyl allyle se cyclisent en存在 de四氯钯酸盐锂 et d'une base pour donner des palladocycles bicycliques qui conduisent aux cyclopentanes par氢化。关于peut ainsi preparer une serie de cetones cycliques
A series of fused tetracycles with a benzene or cyclohexadiene core (2a–h) is satisfactorily prepared by intramolecular [2 + 2 + 2] cycloadditions of triynic and enediynic macrocycles (1a–h) under RhCl(PPh3)3 catalysis; the enantioselective cycloaddition of macrocycles1b and 1e gives chiral tetracycles with moderate enantiomeric excess.
Stereocontrolled construction of rigid tricyclic bis(α-amino acid) derivatives by Ru(Ii)-catalyzed cascade and Diels–Alder reactions
作者:Jon Efskind、Christian Römming、Kjell Undheim
DOI:10.1039/b103254m
日期:2001.10.11
In the preparation of rigid and annulated tricyclic bis(α-amino acid) derivatives the key construction was effected by a Ru(II)-catalyzed RCM cascade reaction of gem-dienynes. The substrates were available by stepwise and stereocontrolled alkynylations and alkenylations of (2R)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazine. The cascade products were bis-heterospiranes or symmetrical or unsymmetrical bis(α-amino acid) derivatives. Tricyclic DielsâAlder adducts were formed between diethyl acetylenedicarboxylate and the diene cascade products. Oxidative aromatization provided rigid tricyclic bis(α-amino acid) derivatives. X-Ray analysis was used to verify configurational assignments.
Certain bromoacetoxy acetylenes used as bactericides
申请人:Stauffer Chemical Company
公开号:US03987195A1
公开(公告)日:1976-10-19
Compounds having the formula ##EQU1## in which R is hydrogen or cyano, and R.sup.1 is hydrogen, alkyl, aryl, nuclear substituted aryl or ##EQU2## R.sup.2 is H or methyl, their method of preparation, and the use of these compounds as biocides, such as in controlling fungi, bacteria, and algae.