Procédé de transformation de N-oxydes d'amines tertiaires en aldéhydes
申请人:RHONE-POULENC NUTRITION ANIMALE
公开号:EP0461972B1
公开(公告)日:1994-03-30
Cyclization of N,N-diethylgeranylamine N-oxide in one-pot operation: preparation of cyclic terpenoid-aroma chemicals
作者:Kunihiko Takabe、Takashi Yamada、Takenori Miyamoto、Nobuyuki Mase
DOI:10.1016/j.tetlet.2008.08.001
日期:2008.10
Acid promoted cyclization of the geranylamine N-oxide (E)-4 followed by base-catalyzed intramolecular aldol condensation afforded 1-acetyl-4,4-dimethyl-1-cyclohexene (7) in one-pot operation. Reduction of 7, which possess strong fruity odor, followed by lipase-catalyzed kinetic resolution furnished the acetate (R)-26 (>49.9% yield, >99% ee) and the recovered alcohol (S)-25 (>49.9% yield, >99% ee, herbal
A Concise Synthesis of
<i>rac</i>
‐
<i>Ambrox</i>
®
<i>via</i>
the Palladium(0)‐Catalyzed Carboalkoxylation of an Allylic Ammonium Salt, as Compared to a Formaldehyde Hetero
<i>Diels–Alder</i>
Approach
作者:Christian Chapuis、David Skuy、Claude‐Alain Richard
DOI:10.1002/hlca.201900097
日期:2019.7
followed by a 1.5 mol‐% Pd‐catalyzed carbomethoxylation of quaternized 31b, leads to the methyl ester 36a. This latter could also be obtained in optically pure form by carbomethoxylation of the corresponding (+)‐acetate. Final reduction‐cyclization may be conducted as earlier described, towards the desired odoriferous rac‐Ambrox® 38a, or its pure (−)‐enantiomer. Generation of a π‐allyl Pd complex from an allylic