Stereospecific synthesis of 2,7-dimethyl-trans,trans-2,6-octadiene-1,8-dial, a tail-to-tail all-trans bifunctional isoprenoid synthetic unit. Convenient synthesis of squalene
Stereospecific synthesis of 2,7-dimethyl-trans,trans-2,6-octadiene-1,8-dial, a tail-to-tail all-trans bifunctional isoprenoid synthetic unit. Convenient synthesis of squalene
Stereoselective synthesis of β-sinensal via a π-allylnickel(<scp>II</scp>) complex
作者:Kikumasa Sato、Seiichi Inoue、Kiyoshi Watanabe
DOI:10.1039/p19810002411
日期:——
A new π-allylnickel(II) complex, di-µ-bromo-bis(1–3-η-2-methyl-6-methyleneocta-2,7-dienyl)dinickel (5) was prepared by the reaction of bromomyrcene (7a) and (8a) with nickel tetracarbonyl in benzene. The reaction of the complex (5) with iodobenzene in dimethylformamide afforded 8-phenylmyrcene (10) in a high degree of stereoselectivity (E/Z= 85/15). The complex (5) reacted with the chloro-acetal (14)
The synthesis of several substrate analogues of the enzyme beta,beta -carotene 15,15'-monooxygenase is reported. The substrate specificity of enriched enzyme fractions isolated from chicken intestinal mucosa was investigated. Regarding substrate binding/cleavage, these experiments demonstrate that i) any deviation from the 'rod-like' beta,beta -carotene structure is not tolerated, ii) one 'natural', unsubstituted beta -ionone ring is required, iii) the position and presence of the Me groups attached to the polyene chain is significant. These results suggest a hydrophobic barrel-like substrate binding site in which the protein's amino acid residues through interaction with the Me groups, direct the central C=C bond in binding distance to the active site's metal-oxo center, supporting the unique regiospecificity of cleavage to retinal (provitamin A).
A new synthesis of α,β-unsaturated aldehydes including (e)2-methyl-2-alkenal