| 摘要 |
Production of polyene aldehydes or dialdehydes of formula ACH=CHC(R<1>)=C(R<2>)CHO (I') or OHCC(R<2>)=C(R<1>)HC=HCBCH=CHC(R<1>)=C(R<2>)CHO (I") comprises: (i) reacting corresponding polyene O,O-dialkyl acetals or di-(O,O-dialkyl acetals) of formula ACH(OR<3>)2 (II') or (R<3>O)HCBCH(OR<3>)2 (II") with 1-alkoxy-1,3-dienes of formula CH2=C(R<1>)C(R<2>)=CHOR<4> (III) in the presence of a Lewis or Bronsted acid; (ii) hydrolysing the reaction mixture; and (iii) cleaving off the alcohol R<3>OH under basic or acidic conditions from the resulting compounds ACH(OR<3>)CH2C(R<1>)=C(R2)CHO (IV') or OHCC(R<2>)=C(R<1>)H2CHC(OR<3>)BCH(OR<3>)CH2C(R<1>)=C(R<2>)CHO (IV") to give (I') or (I'') respectively. A = monovalent conjugated polyene group optionally substituted by Me; B = divalent conjugated polyene group optionally substituted by Me; CH=CH-CR<1>=CR<2>-CHO form the terminal group(s) of A and B; R<1>, R<2> = H or Me; R<3>, R<4> = 1-6C alkyl. Also claimed are compounds (IV') and (IV"), especially compounds in which A = a group of formula (a) or (b), or B = a group of formula (c"). R<5>, R<6> = H, optionally protected OH or optionally protected oxo group; m = 0-4; n, r = 0 or 1; p = 0-2; and q = 0-3. |
