Syntheses and some reactions of aliphatic 1,2,3‐trienes

摘要: Trienes of the type R(R′)CCCCH2 (R and R′ are H or alkyl) have been prepared in good to excellent yields from 1,4-dichloro-2-alkynes, R(R′)C(Cl)CCCH2Cl, zinc dust sodium iodide dimethyl sulfoxide. The dichloro compounds were obtained corresponding 1,4-dihydroxy-2-alkynes thionyl chloride. The 1,4-diols synthesized propargyl alcohol; adduct this alcohol 2,3-dihydropyran, , was coupled with an aldehyde RCHO a ketone RR′CO under Grignard conditions. The resulting products R(R′)C(OH)CCCH2OT.H.P. (T.H.P. = tetrahydropyranyl) treated catalytic amount p-toluenesulfonic acid excess methanol, furnishing diols R(R′)C(OH)CCCH2OH alkyl R both overall yields. Reaction cumulenes equivalent amounts alkali amide liquid ammonia followed by hydrolysis reaction mixtures afforded isomeric 3,1-enynes, R(R′)CCHCCH, yields. Buta-1,2,3-triene, CH2CCCH2, hexa-1,2,3-triene, CH3CH2CHCCCH2, isomerized methoxide enynes vinylacetylene, HCCCHCH2, hex-2-en-4-yne, CH3CHCHCCCH3, respectively. In case buta-1,2,3-triene also considerable quantity 1,4-adduct 1-methoxy-2-butyne, CH3CCCH2OCH3, isolated. The addition ethanethiol hexa-1,2,3-triene proceeded readily, yielding adducts, C2H5SCH2CHCCH2 C2H5SCH2CCCH3, first case, C2H5CH(SC2H5)CHCCH2, C2H5CH(SC2H5)CCCH3 C2H5SCH2CHCCHC2H5, second case. These lost when ammonia, HCCCHCH2 HCCCHCHC2H5, respectively, being produced.