Synthesis of (Z,Z)-11,13-hexadecadienal, a principal component of navel orangeworm (Pamyelois transitella) pheromone

New Synthesis of (11Z,13Z)-11,13-Hexadecadienal, the Female Sex Pheromone of the Navel Orangeworm

“…8) A critical examination of all the published syntheses indicates that the preparation of 1 in a multi-gram-scale was not an easy task due to the non-reproducibility of some of the earlier works. This paper reports my experimental result, which gives a multi-gram quantity of 94-95% pure 1.…”

“…A solution of dicyclohexylborane was prepared by adding dropwise a boranedimethyl sulfide complex (1.8 ml, d 1.287, 2.3 g, 30 mmol) to a stirred and ice-cooled solution of cyclohexene in dry THF (2 M, 26 ml, 52 mmol) at 5-10 C under argon. The mixture was stirred for 30 min at [5][6][7][8][9][10] C to give a slurry of crystalline dicyclohexylborane. A solution of 9 (2.7 g, 8.8 mmol, 5 ml) was added dropwise to the stirred and ice-cooled mixture.…”

Insect pheromones and related natural products

“…A highly efficient enantiomer-specific route has also been reported from ( +)-(S)-lactic acid (Scheme 22); this four-step route proceeded in an impressive overall yield of 73%.225 The chiral synthon (1 39), discussed earlier, has also been utilized in an alternative synthesis226 and ( -)-frontalin has been prepared from the (2S,3R)-dione prepared from cr-methylcinna- The use of boronic esters of pinanediol, following an improvement in the synthesis of chiral a-chloro-boronic esters, has been demonstrated in a synthesis of (1 R,SS,7R)-exobrevicomin (1 73) (Scheme 23).230 An alternative procedure utilized diethyl (-)-(S,S)-tartrate as starting material in a sixstep sequence (Scheme 24).23 Inevitably, routes from sugar derivatives have also been investigated for a synthesis of (+)exo-brevicomin ; one starting point was D-glucose, which was transformed into the hex-5-enofuranose (1 74) (Scheme 25).232 In this synthesis, no attempt was made to purify the Wittig adduct (174), and hydrogenation was carried out on the crude material. A similar approach has also been followed from a nona-3,s-dienulose derivative.233 A high diastereomeric selectivity has been observed in the reaction of a Grignard reagent with a chiral wbenzyloxy-aldehyde, and this reaction has been used in a synthesis of (+)-exo-brevic~min.~~~ Treatment of the Reagents: i, LiCHCl,, at -100 "C; ii, ZnCl,; iii, LiOCH2Ph; iv, EtMgBr, at -78 "C; v, H20z, NaOH, H + , SiO,; vi, H2, Pd Scheme 23…”

Facile and Efficient Syntheses of (11Z,13Z)-Hexadecadienal and Its Derivatives: Key Sex Pheromone and Attractant Components of Notodontidae

“…The structures of (11 Z ,13 Z )-hexadecadienal ( 1 ), (11 Z ,13 Z )-hexadecadienol ( 2 ), and (11 Z ,13 Z )-hexadecadien-1-yl acetate ( 3 ) contain a conjugated ( Z , Z )-diene moiety. The construction of the ( Z , Z )-conjugated diene system has been achieved in the past using a series of schemes: (1) the Wittig reaction: addition reaction of aldehyde with a Z type-unsaturated enol [13]; (2) Cadiot–Chodkiewicz coupling coupled with hydroboration-protonolysis of 1,3-diyne [14]; (3) diimide reduction of acetylene and palladium-catalyzed coupling [15]; and (4) catalytic coupling of metal catalysts and hydroboration-protonolysis [16,17,18,19,20,21,22].…”

“…Furthermore, both (11 Z ,13 Z )-hexadecadienal ( 1 ) and ( Z )-13-hexadecen-11-ynal ( 4 ) possess the labile terminal formyl group, therefore the timing of placing the terminal formyl group is also important, owing to the fact that oxidation in the final step may isomerize the ( Z , Z )-conjugated diene system [22]. The formyl group is introduced into its intermediate as acetal derivatives in an earlier stage of synthesis, which has been shown to avoid isomerization of the ( Z , Z )-conjugated diene system from oxidation [17,18,19,20].…”