4‐Alkyl‐ und 4‐Aryl‐Δ³‐arsenine sowie 4‐Alkyl‐ und 4‐Aryl‐2‐benzyl‐Δ³‐arsenine durch 4‐Methoxy‐1,4‐dihydro‐arsenin‐Arsenin‐Umlagerung

Abstract

(1 2,4Z)-1,5-Dilithio-(3R)-3-methoxy-l ,Cpentadiene (R = Alkyl, Aryl) reagieren mit ferf-Butyl-(dich1or)arsin zu den E/Z-isomeren l-ferf-Butyl-(4R)-4-methoxy-l,4-dihydroarseninen, die unter H +-Katalyse zu den 4R-Arseninen aromatisieren. Die 'H-NMR-, 'k-NMR-und MassenSpektren der 1 ,4-Dihydroarsenine und Arsenine werden diskutiert. Die l-(Diethylamino)-(4R)-4-methoxy-I ,4-dihydroarsenine gehen in Abhangigkeit von R bei der Umsetzung mit Salzsaure in

Synthesis and Rearrangement of 3-Methyl-1,4-pentadiyne-3-ol

“…3-Methyl-1,4-pentadiyne-3-ol ( 1 ) was first synthesized by Böhm-Gössel et al as an intermediate [ 8 ]. The synthesis of 1 could also be achieved using various methods [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ] summarized in Scheme 1 . Disadvantages of these methods are, however, the formation of toxic wastes and low yields.…”

“…Compound 1 could also be synthesized starting from 1-butyne-3-ol by oxidation [ 13 ] and subsequent ethynylation with the ethynyl Grignard reagent [ 8 ]. A more convenient synthesis of 1 was described by Märkl and Liebl , in which methyl acetate and ethynyl magnesium chloride were used [ 14 ]. The main disadvantage of this route is the handling of ethyl chloride, needed for the preparation of ethyl magnesium chloride which is later transformed to ethynyl magnesium chloride.…”