- Wittig olefination of menthone lactol and its aluminate
-
Features of the Wittig olefination reaction of menthone lactol and its aluminate by several n-alkylidenetriphenylphosphoranes were studied. The product of the reaction with ethylidenetriphenylphosphorane was used in the synthesis of the sex pheromone of p
- Ishmuratov,Vydrina,Nazarov,Galkina,Yakovleva,Lobko,Muslukhov,Tolstikov
-
-
Read Online
- A New Asymmetric Synthesis of (S)-14-Methyloctadec-1-ene, the Sex Pheromone of the Peach Leafminer Moth
-
Abstract: An asymmetric synthesis of 14-methyl-1-octadecene, the sex pheromone of thepeach leafminer moth has been achieved. Based on the asymmetric methylation ofchiral (S)-4-benzyloxazolidin-2-one, thecarbon chain of the target molecule was assembled through aC1+C10+C4+C3procedure. The γ-lactone was transformed into 4-(benzyloxy)butanoic acid andthen, with the induction of Evan’s template, a chiral methyl group wasintroduced to the position of the carboxylic group in 97percent de. After reduction and a couple of chemicaloperations, the designed key intermediate A1was obtained. The synthesis of another moiety was started from decane-1,10-diolwhich was selectively protected and oxidized. The long carbon chain wasinstalled according to a Wittig protocol. After deprotection, oxidization, andmethylenation, the target molecule was synthesized in 7 linear steps with anoverall yield of 30.3percent.
- Bai, Hongjin,Du, Zhen-Ting,He, Guo-Guo,Liu, Lu,Tang, Meng,Wei, Liang,Zhang, Tao
-
p. 1089 - 1095
(2020/07/25)
-
- Neutral iridium catalysts with chiral phosphine-carboxy ligands for asymmetric hydrogenation of unsaturated carboxylic acids
-
We developed neutral iridium catalysts with chiral spiro phosphine-carboxy ligands (SpiroCAP) for asymmetric hydrogenation of unsaturated carboxylic acids. Different from the cationic Crabtree-type catalysts, the iridium catalysts with chiral spiro phosphine-carboxy ligands are neutral and do not require the use of a tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF?) counterion, which is necessary for stabilizing cationic Crabtree-type catalysts. Another advantage of the neutral iridium catalysts is that they have high stability and have a long lifetime in air. The new iridium catalysts with chiral spiro phosphine-carboxy ligands exhibit unprecedented high enantioselectivity (up to 99.4% ee) in the asymmetric hydrogenations of various unsaturated carboxylic acids, particularly for 3-alkyl-3-methylenepropionic acids, which are challenging substrates for other chiral catalysts.
- Yang, Shuang,Che, Wen,Wu, Hui-Ling,Zhu, Shou-Fei,Zhou, Qi-Lin
-
p. 1977 - 1980
(2017/03/09)
-
- A facile asymmetric synthesis of (S)-14-methyl-1-octadecene, the sex pheromone of the peach leafminer moth
-
An asymmetric synthesis of 14-methyl-1-octadecene, the sex pheromone of the peach leafminer moth has been achieved. The target molecule was synthesized in six linear steps and in 30.3% overall yield from commercially available hexanoyl chloride, (S)-4-benzyloxazolidin-2-one and 1,9-nonanediol. The hexanoyl chloride was connected with (S)-4-benzyloxazolidin-2-one, and with the induction of the chiral oxazolidinone auxiliary, after chiral methylation, LAH reduction and then tosylation gave the chiral key intermediate 5 in high stereoselectivity. 1,9-Nonanediol, was selectively brominated, THP protected and subjected to Li2CuCl4-mediated C-C coupling to afford a C12 intermediate. The target molecule, (S)-14-methyl-1-octadecene, was obtained after the two parts were subjected to a second Li 2CuCl4-mediated C-C coupling. Our synthetic approach represents the first time a substrate-control asymmetric synthesis of (S)-14-methyl-1-octadecene has been reported.
- Zhang, Tao,Ma, Wei-Li,Li, Tian-Rui,Wu, Jia,Wang, Jun-Run,Du, Zhen-Ting
-
p. 5201 - 5208
(2013/06/27)
-
- (S,S)-(+)-pseudoephedrine as chiral auxiliary in asymmetric conjugate addition and tandem conjugate addition/α-alkylation reactions
-
(Chemical Equation Presented) Organolithium reagents undergo highly regio- and diastereoselective 1,4-addition to (S,S)-(+)-pseudoephedrine enamides furnishing the corresponding β-alkyl-substituted adducts in excellent yields and diastereoselectivities. In addition, the intermediate lithium enolates generated after the conjugate addition step undergo a highly diastereoselective alkylation reaction, furnishing α,β-dialkyl- substituted amides in high yields. The obtained adducts have been converted into chiral nonracemic β-alkyl- and α,β-dialkyl-substituted carboxylic acids and γ-alkyl- and β,γ-dialkyl-substituted alcohols using very simple and high-yielding procedures.
- Reyes, Efraim,Vicario, Jose L.,Carrillo, Luisa,Badia, Dolores,Uria, Uxue,Iza, Ainara
-
p. 7763 - 7772
(2007/10/03)
-
- (R)-4-menthenone in the synthesis of optically pure sex pheromone of the peach leafminer moth (Lyonetia clerkella)
-
The synthesis of (14S)-methyloctadec-1-ene, sex pheromone of the peach leafminer moth (Lyonetia clerkella), is described to demonstrate a new potential of the synthetic use of (R)-4-menthenone.
- Kharisov,Latypova,Talipov,Muslukhov,Ishmuratov,Tolstikov
-
p. 2267 - 2269
(2007/10/03)
-
- Preparation of the Versatile Chiron, (R)- and (S)-12-(Tetrahydropyranyloxy)-3-methyldodecanol: Application to the Syntheses of Methyl Branched Insect Pheromones
-
A convenient chemoenzymatic synthesis for the title methyl branched chiron has been developed starting from 10-undecenoic acid (1).Thus, 1 was converted to 1-(tetrahydropyranyloxy)-10-undecan-2-one (4) which on reaction with triethyl phosphonoacetate and
- Sankaranarayanan, S.,Sharma, A.,Kulkarni, B. A.,Chattopadhyay, S.
-
p. 4251 - 4254
(2007/10/02)
-
- Pheromone Syntheses, LXXVII. - New Synthesis of the Enantiomers of 14-Methyl-1-octadecene, the Pheromone of Lyonetia clerkella L.
-
The synthesis of the title compounds (R)-1 and (S)-1 from (R)-citronellic acid (R)-2 is described.
- Mori, Kenji,Kato, Minoru
-
p. 2083 - 2087
(2007/10/02)
-