Dihydroactinidiolide

E. Guichard, A. Kustermann and A. Mosandl, Chkal flavour compounds from apricots. Distr ibution of -) lactones enantiomers and stereodifferentiation of dihydroactinidiolide using multi-dimensional gas chromatogr aphy , 7. Chromatogr. 498 396-401 (1990). 

The use of chiral bis(oxazoline) copper catalysts has also been often reported as an efficient and economic way to perform asymmetric hetero-Diels-Alder reactions of carbonyl compounds and imines with conjugated dienes [81], with the main focus on the application of this methodology towards the preparation of biologically valuable synthons [82]. Only some representative examples are listed below. For example, the copper complex 54 (Scheme 26) has been successfully involved in the catalytic hetero Diels-Alder reaction of a substituted cyclohexadiene with ethyl glyoxylate [83], a key step in the total synthesis of (i )-dihydroactinidiolide (Scheme 30). 

Figure 2. Structure of dihydroactinidiolide, an allelopathic compound isolated from Eleocharis coloradoensis.

Scopoletin and dihydroactinidiolide (Figure 8) are found in green coffee.3... 

Syntheses have been reported for several other natural products related structurally to carotenoids, viz. dihydroactinidiolide (123) and tetrahydroactinidiolide (124), trans- and cis-a-damascone (125), dihydroedulans I and II, (51) and (52), bicyclodamascenones A and B, (53) and (54), the diastereoisomeric caparrapi oxides (126), ( )-a-chamigrene (127), and the novel passion-fruit ionone derivatives (47) and (48). ... 

Klok, J. Baas, M. Cox, H.C. de Leeuw, J.W. Schenck, P.A. (1984) Loliolide and dihydroactinidiolide in a recent marine sediment probably indicate a major transformation pathway of carot ioids. Tetrahedron Lett., 25, 5577-80. 

In the flavour extract of apricots, racemic dihydroactinidiolide (DHA) was found as the first natural racemate detected by enantio-MDGC analysis [16]. The absolute configurations and the optical activities have been reported to be (R)-(-) and (S)- +) enantiomers, respectively [17, 18]. 

Fig. 17.4 Chromatographic behaviour of dihydroactinidiolide (DHA) enantiomers synthetic racemate (a) DHA fractionation by enantioselective high-performance liquid chromatography (HPLC) (b). Chiral selectors used in enantio-GC DIME-jS-CD (30%) in SE 52 DIAC-jS-CD (30%) in PS 268 DIAC-/1-CD (50%) in OV 1701. Order of elution R (I), S (II) in all cases [13], DIME heptakis(2,3-di-0-methyl), CD cylclodextrin, DIAC heptakis(2,3-di-0-acetyl)...

It was found that extracellular liquid of the fungus can degrade -carotene to j -cyclocitral, dihydroactinidiolide, 2-hydroxy-2,6,6-trimethylcyclohexanone, -apo-lO -carotenal and -ionone the last two compounds are the main prod-... 

This allyloxylation was used to produce d,l-rose oxide from citronellol (Eq. 50) 1 -Similarly d, 1-dihydroactinidiolide was formed in one step by the intramolecular oxyselenation-deselenation sequence (Eq. (51))... 

The electrochemical oxyselenenylation-deselenenylation of alkenes was demonstrated by a one-step 92% synthesis of ( )-dihydroactinidiolide (187) from the carboxylic acid (186) (81JA4606). 

Oxidation of a p,y-ena/.2 The gradual addition of CIQH4CO3H (2 equiv.) to the p, y-enal 1 in refluxing CHC13 (17 hours) results in formation of the phytotoxin dihydroactinidiolide (2) in 83% yield. However, if the reaction is conducted in... 

Demethoxydaunomycinone, 71 1-Deoxynojirimycin, 175 Dihydroactinidiolide, 77 Dihydrosphingosine, 31 25,28-Dihydroxy-7,8-dihydroergosterol, 151 Dodecahedrane, 251 (Z)-8-Dodecenyl-l-acetate, 281... 

Hydrogenation of 2,4,4-trimethyl-2-cyclohexenone with rrans-RuCl2(tolbinap)(dpen) and (CH3)3COK under 8 atm of hydrogen gives 2,4,4-trimethyl-2-cyclohexenol quantitatively with 96% ee (Scheme 1.70) [256,275,276]. In this case, unlike in the reaction of aromatic ketones, the combination of the R diphosphine and S,S diamine most effectively discriminates the enantiofaces. The chiral allylic alcohol is a versatile intermediate in the synthesis of carotenoid-derived odorants and other bioactive terpens such as a-damascone and dihydroactinidiolide [277]. 

The synthetic applicability of the electrochemical oxy-transposition may be demonstrated by the one-step synthesis of d -dihydroactinidiolide 60 from the carboxylic acid 59 in 73 % yield. The lactone 60 may be produced by electrochemical intramolecular oxyselenylation followed by elimination of selenic acid (Scheme 3-21)68>. 

An improved synthesis of the Cn-terpenic lactone Dihydroactinidiolide was described by A.K. Bose et al. [35]. The synthesis started from a commercially available aldehyde that was subjected to treatment with m-CPBA and a catalytic amount of PTSA (Scheme 10). The intermediate epoxy acid underwent cyclization resulting in the formation of Aeginetolide. Dehydration has been reported earlier by heating of this compound with aqueous NaOH, at 60 °C for 24 h, or with SOCI2 and pyridine at room temperature for 5 h. The authors observed expeditious and convenient dehydration of this compound supported on silica gel, under microwave irradiation for 5 -10 min (domestic oven), yielding Dihydroactinidiolide in 80% yield. 

Among the other reported volatile TDP of B-carotene include B-cyclo-cltral, 5,6-epoxy-B-ionone and dihydroactinidiolide (25). These compounds were also found by Isoe et al. (30, 31), Wahlberg et al. (32) and Kawakami and Yamanishi (33) as photo-oxygenation products of B-carotene. Volatile thermal degradation of carotenoids has been extensively studied, mainly in nonfood systems. Hence, the objective of this study was to identify the volatile components of the TDP of B-carotene formed in a food model system. 

The formation mechanism of the oxygenated products, namely ionone series compounds and the lactones—dihydroactinidiolide can be said to be very similar to those of Isoe et al. (30), as well as the dioxethane mechanism by Ohloff (36). They proposed that singlet oxygen is involved by direct cyclo-addition to the double bond. 

Thus, oxygen attack at the terminal 5,6-double bond position, followed by the formation of a peroxy epoxide and cleavage of the C-C and 0-0 bonds, resulted in 5,6-epoxy-B-ionone, while rearrangement of the 5,6-epoxy derivative, followed by reduction and oxidation, resulted in the formation of dihydroactinidiolide. Furthermore, a peroxy derivative was formed and cleaved to form 8-ionone, which then led to the formation of dihydroactinidiolide as a secondary oxidation product. 

The aroma concentrate from hoji-cha has a strong characteristic roast aroma. Hoji-cha produced about 3 times the aroma concentrate than the original ban-cha. From the basic fraction which comprised 29% of the aroma concentrate, 19 different pyrazines were identified. The neutral fraction which was 47% of the aroma concentrate contained furans and pyrroles along with the original tea aroma. In addition, ionone related compounds such as theaspirone, dihydroactinidiolide and a large amount of B-ionone were found in the neutral fraction. Table III shows the increase of furan and pyrrole content due to roasting of the ban-cha (4). 

Ten volatile compounds were produced from the pyrolysis of 6-carotene. Among them, toluene, xylene, IJ-cyclocitral, ionene, B-ionone, 5,6-epoxy-B-ionone and dihydroactinidiolide were identified. The addition of catechin gallates reduced the quantity of the ten... 

In another study, 13-carotene was heated in aqueous medium at 90°C, 120°C and 150°C. More than 40 different compounds were found in the ether extracts by GC-MS as shown in Figure 3. Dihydroactinidiolide (sweet peachy aroma) was found in highest concentration at all temperatures studied. At 90°C, 5-6-epoxy-6-ionone (sweet, violet-like) was found in second highest quantity, while at 150°C, 2,6,6-trimethyl-2-hydroxy-cyclohexanone (green, citrusy) and 2,6,6-trimethyl-2-hydroxy-cyclohexan-1-aldehyde (floral, geraniol-like) were found in large quantity. At 120°C, these compounds were more evenly balanced than at 90°C or 150°C. A balance of ionone related compounds seem to contribute to an attractive green tea flavor. 

---