JPH0355451B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to a novel method for producing compounds having conjugated carbon and carbon unsaturated bonds. (Prior art) Compounds having conjugated carbon and carbon unsaturated bonds are interesting substances due to their properties as organic semiconductors.
Further, isoprenoid-based conjugated polyene compounds are important as precursors of vitamin A or other physiologically active substances or their precursors. Conventionally, only synthetically inconvenient methods have been known for producing such conjugated unsaturated compounds, such as stepwise formation of double or triple bonds or elongation of conjugated chains by formation of carbon-carbon bonds. (Object of the invention) The present invention provides that, in the β-position relative to the sulfonyl group,
The present invention provides a method for easily synthesizing useful conjugated unsaturated compounds by carrying out desulfonation and dehydroxylation at once under simple and mild conditions using a compound having a protected hydroxy group. . (Structure of the Invention) The present invention relates to the following general formula () having a protected hydroxy group at the β position relative to the sulfonyl group.
This is a method for producing a conjugated unsaturated compound, which is characterized by treating a sulfone represented by the formula with potassium tert-butoxy. However, in formula (), Y is -CH=CH- or -C≡C-, R is a phenyl group, and ^R1 is an aliphatic group which may have a substituent inert to tert-butoxypotassium. A hydrocarbon group, R ² is hydrogen or a group defined similarly to R ¹ , R ³ is hydrogen or a tetrahydropyranyloxy group, R ⁴ is an acetyl group or a tetrahydropyranyl group, and n is 0 or a positive integer. The present invention is represented by the following reaction formula. As shown in the above formula (), the present invention can be said to be a synthetic method in which the conjugated chain of the unsaturated bond in the carbon skeleton of the sulfone starting material is extended by two places. For example, n=0
In the case of , a diene compound is produced, and in the case of n=1, when Y is a double bond, the product is a triene compound, and when Y is a triple bond, an ene-yn-ene compound is produced. Furthermore, a major feature of the present invention is that the double bond produced has an extremely high production rate of the trans isomer, and some compounds show a substantially 100% trans isomer production rate. In the present invention, β used as a starting material
Sulfones having a protected hydroxy group at the - position can be easily synthesized, for example, by adding a compound having a suitable sulfonyl group and an aldehyde, as shown in the following formula (). According to the formula (), a suitable sulfone is anionized with, for example, n-butylated lithium (n-BuLi) and reacted with an aldehyde, and the resulting hydroxy compound is anionized with, for example, acetic anhydride (Ac ₂ O). A protecting group (acetyl group) can be introduced into the hydroxyl group by a conventional method involving the action of +pyridine (Py). As the protecting group, an acetyl group and a tetrahydropyranyl group, which are commonly used in organic synthesis reactions, are used. The polyene-forming reaction of the present invention is an elimination reaction between a sulfonyl group and a β-hydroxy group, as shown in the above formula (), and the reaction is extremely easy. That is, the object is achieved by treating the starting material sulfone with potassium tert-butoxy using tetrahydrofuran or a mixture of tetrahydrofuran-tert-butanol as a solvent. In this case, the starting material compound of formula () is a fatty acid which may have a substituent that does not interact with tert-butoxypotassium in which R ¹ is a strong alkali, such as an ethylenedioxy group or a tetrahydropyranyloxy group. It must be a compound in which R ² is hydrogen or an aliphatic hydrocarbon group similar to R ¹ above. Potassium tert-butoxy is used in an amount equivalent to or more, usually about 2.5 to 15 moles, per mole of sulfone.
A reaction temperature of room temperature to reflux temperature is sufficient, and the reaction time varies depending on the sulfone used and is not particularly limited. (Example) Examples 1 to 7 Using the starting materials shown in Table 1, corresponding conjugated unsaturated compounds were produced. In the table, the molar ratio of t-BuOK (potassium tert-butoxy) is expressed as t-BuOK/starting material. Product yields are values obtained by column chromatography purification. In addition, THF is tetrahydrofuran, t-
BuOH represents tertiary butanol, THP represents a tetrahydropyranyl group, Ph represents a phenyl group, Ac represents an acetyl group, and Me represents a methyl group.

【table】

[Table] The nuclear magnetic resonance spectra of the products of Examples 1 to 7 were as follows. Example 1: ¹ H NMR (CCl ₄ ) δ0.76−1.13 (m,
3H, CH ₃ ), 1.00(d, 6H, C(CH ₃ ) ₂ , J=
6.8Hz, 1.27-1.70 (m, 8H, _CH2 ), 1.76-2.61
(m, 3H, _CH2C =C, CHC=C), 4.86−6.36
(m, 4H, CH=CH). ^13C NMR ( _CDCl3 )
δ122.6, 127.4, 128.7, 130.3, 132.6, 139.3,
141.5 (olefinic carbons). Example 2: ¹ H NMR (CCl ₄ ) δ0.80 (t, 3H,
_CH3 , J=4Hz), 1.00-1.50(m, 10H,
CH ₂ ), 1.50−2.20 (m, 2H, CH ₂ C=C), 4.60
-6.40 (m, 5H, C=CH ₂ , C=CH), ^13C
NMR ( _CDCl3 ) δ114.5, 130.9, 135.6, 137.4
(olefinic carbons). Example 3: ¹ H NMR (CCl ₄ ) δ1.00 (d, 6H, C
( _CH3 ) ₂ , J=6.8Hz), 1.34(s, 1.80H, _CH3 ),
1.41 (s, 1.20H, CH ₃ ), 2.00−2.60 (m, 1H,
CHC=C), 3.80 (s, 4H, OCH ₂ CH ₂ O),
5.00−7.00 (m, 4H, CH=CH) Example 4: ¹ H NMR (CCl ₄ ) δ0.79 (t, 3H,
_CH3 , J=4Hz), 0.95-1.70(m, 14H,
CH ₂ ), 1.80 (s, 6H, CH ₃ ), 2.42 (t, 2H,
CH ₂ CO, J = 7Hz), 5.80 (d, 1H, C = CHC
= CCO, J = 12Hz), 5.90 (d, 1H, C =
CHCO, J=15Hz), 7.27(dd, 1H, CH=
CCO, J=15, 12Hz). Example 5: ¹ H NMR (CCl ₄ ) δ1.00 (d, 6H, C
( _CH3 ) ₂ , J=6Hz), 0.70−1.00(m, 3H,
_CH3 ), 1.11-1.59 (m, 4H, _CH2 ), 1.80-2.60
(m, 3H, CHC=C, _CH2C =C) 5.00−6.40
(m, 6H, CH=CH) Example 6: ¹ H NMR (CCl ₄ ) δ1.50 (s, 3H,
CH ₃ ), 1.58 (s, 3H, CH ₃ ), 1.68 (s, 6H,
CH ₃ , ), 1.79 (s, 3H, CH ₃ ), 1.90−2.20 (m,
4H, CH ₂ , C=C), 4.70-5.15 (m, 1H, C
= CH), 5.58-6.60 (m, 7H, C=CH). Example 7: ¹ H NMR (CCl ₄ ) δ0.70−1.05 (m,
3H, CH ₃ ), 0.94(d, 6H, C(CH ₃ ) ₂ , J=
6.8Hz), 1.07-1.63 (m, 8H, _CH2 ), 2.00-
2.45 (m, 3H, CHC=C, _CH2C =C), 5.11−
6.57 (m, 4H, CH=CH).

Claims (1)

[Claims] 1. A conjugated unsaturated compound characterized in that a sulfone represented by the following general formula () having a protected hydroxy group at the β position relative to a sulfonyl group is treated with potassium tert-butoxy. manufacturing method. However, in formula (), Y is -CH=CH- or -C≡C-, R is a phenyl group, and ^R1 is an aliphatic group which may have a substituent inert to tert-butoxypotassium. A hydrocarbon group, R ² is hydrogen or a group defined similarly to R ¹ , R ³ is hydrogen or a tetrahydropyranyloxy group, R ⁴ is an acetyl group or a tetrahydropyranyl group, and n is 0 or a positive integer.