The determination of the absolute configurations of some phenylallenecarboxylic acids

✍ Scribed by Keiji Shingu; Sanji Hagishita; Masazumi Nakagawa

• Book ID: 104240958
• Publisher: Elsevier Science
• Year: 1967
• Tongue: French
• Weight: 202 KB
• Volume: 8
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)89692-1

✦ Synopsis

We wish to report the synthesis , resolution and the determination of the absolute configurations of some phenylallenecarboxylio arids (I).

PhYc=C=CRCOoli

(I, R=H, He, Et, &-Pr and &-&a) R' Phenylallenecarboxylic acid (I, R=H) was procedure (l), and the other acids (I, R=Me, the method outlined in the folowing chart. p>Hcocl PhsP=CHCOOEt PhaP= -COOEt r: O=C-H-Ph '5( OK Phi prepared according to the known Et and A-Pr) were synthesised by pyrolysis (2) Ph, . CH-Cxe-COOW R' c =C=CBCOOH (I, R=Me, Et Phenyl-i-butylallenecarboxylic acid (I, R=s-Bu), too, the same reactions, but the following route was found to and &-Pr) could be obtained by be more convenient. Ph\ SOCls (3) Ph, 1) Mg -c-CSCB . /c -=C=c!HCl e &-B/OH (I, R=&-Bu)* j_-Bu 2) coa These racemic acids were resolved via the cinchonidine salts. 'lhe (+)isomers were obtained excepting the case of R=Et which gave the (-)-enantiomer.

* lhe attempt to prepare the optically active acid starting from the active chloroallene failed due to the complete racemisation.