86254-75-3Relevant articles and documents
Preparation et proprietes des -1 alcen-1(Z) ols-3
Ruel, Odile,Ekogha, Cyriaque Bibang Bi,Lorne, Robert,Julia, Sylvestre A.
, p. 1250 - 1260 (2007/10/02)
The 92percent regioselective nucleophilic trans-addition of 2-methyl-2-propanethiol to primary, secondary and tertiary 1-alkyn-3-ols 1, catalyzed by 0.1 equiv. of potassium hydroxide powder, affords good yields of anti-Markownikoff products 2.These compounds 2 can be readily hydrolysed into the corresponding α,β-unsaturated aldehydes 7 either by dilute aqueous sulfuric acid or more generally by use of cupric salts in aqueous acetone.The 1-(1',1'-dimethyl ethyl)thio-3-methyl-1(Z)-buten-3-ol 2f treated first with potassium hydride and then with n.butyllithium in THF at -78 deg C, readily furnished the corresponding K(1+) Li(1+) dianion 10f which was treated successfully with some electrophiles: methyl and butyl iodides, trimethylsilyl chloride, dimethyl disulfide and isovaleraldehyde, to afford the alkylated products 11f.The primery and secondary alcohols 2a,c,d gave poor to moderated yields.Some of the alkylated products 11f (R3 = n.C4H9 and Si(CH3)3) were hydrolysed to the corresponding carbonyl compounds 19 by use of methyl iodide in aqueous acetonitrile.The hydroxyl group of compounds 2 is methylated with methyl iodide and sodium hydride to afford the corresponding (Z) methyl ethers 12a-d,f.The isomeric (E)-methyl ether 20a was obtained from the (Z)-propenol derivative 2a by treatment with methanesulfonyl chloride and triethylamine at -40 deg C in CH2Cl2 followed by in situ methanolysis.Reaction of the (Z)-alkenols 2b,c,d with trimethyl orthoformate and 10 mole percent trifluoroacetic at 0 deg C furnished readily the pure methoxy-(E)-isomers 20b,c,d.Following a previous communication (21) on the dehydration of compound 2f to the corresponding (E)-isoprenic sulfide, the tertiary alcohol-sulfide 2h is smoothly dehydrated in acidic conditions to afford the (E)-dienic sulfide 23.Finally, the primary and secondary alcohol-sulfides 2a,b,d can be oxidized to the corresponding carbonyl compounds 24a,b,d.
