137037-08-2

Upstream product

• 78-85-3 2-methylpropenal 
• 1515-76-0 1-acetoxy-1,3-butadiene 

Downstream Products

• 106758-72-9 (1S,2S)-2-(hydroxymethyl)-2-methylcyclohexanol 
• 155907-01-0 (1S,6S)-6-(hydroxymethyl)-6-methyl-2-cyclohexenol 

Relevant academic research and scientific papers

Diazepane Carboxylates as Organocatalysts in the Diels–Alder Reaction of α-Substituted Enals

Ethyl diazepane carboxylate efficiently catalyzes the Diels–Alder cycloaddition of α-substituted-α,β-unsaturated aldehydes via iminium ion organocatalysis. The reaction is applicable to a range of dienes and dienophiles and generally proceeds at room temperature in the presence of 5 mol-% catalyst and 2.5 mol-% triflic acid co-catalyst. The incorporation of a stereogenic center on the diazepane backbone in combination with a menthyl carbamate produces a catalyst which affords enantioselectivities of 70–95 % ee for the cycloaddition of cyclopentadiene with a range of dienophiles. The enantioselectivity is rationalized via a transition state in which electrostatic stabilization by the carboxylate directs the diene to the more hindered face of the dienophile.

Asymmetric catalysis of Diels-Alder cycloadditions by an MS-free binaphthol-titanium complex: Dramatic effect of MS, linear vs positive nonlinear relationship, and synthetic applications

Asymmetric Diets-Aider (D.-A.) reaction of 5-hydroxynaphthoquinone (juglone) with butadienyl acetate catalyzed by the binaphthol-derived chiral titanium (BINOL-Ti) complex 1 proceeds in only 9% ee in the presence of molecular sieves (MS). Remarkably, however, this reaction proceeds in 76-96% ee with BINOL-Ti complex 1 freed from MS to provide the endo-adducts useful for the synthesis of anthracyclines and tetracyclines. The solid MS-free BINOL-Ti complex 1 is stable for months at -20°C. Enhancements in endo selectivity and asymmetric induction are observed with the MS-free BINOL-Ti 1 also in the catalyzed D.-A. cycloaddition of methacrolein and glyoxylate with 1,3-dienol ethers and esters. The glyoxylate adducts can be converted to the mevinolin (compactin) intermediates. Surprisingly, the MS-free complex 1 exhibits not only a linear relationship between the ee's of BINOL-Ti 1 and the D.-A. products but also a positive nonlinear effect (asymmetric amplification), depending simply on the mixing manner of (R)-1 with (S)-1 or (±)-1.

Diels-Alder Route to Potential Trichothecene Precursors

2-Methyl-3-yn-2-ol (9) is efficiently converted into 6-formyl-3,6-dimethylcyclohex-2-enyl acetate (4b) and into 6-acetyl-3,6-dimethylcyclohex-2-enyl acetate (4c) via highly regio- and stereo-selective Diels-Alder cycloadditions of 3-methylbuta-1,3-dienyl acetate (2b).The cycloadduct (4b) is converted by base into 4a,5,6,8a-tetrahydro-4a,7-dimethylcoumarin (13b), whilst the cycloadduct (4c) yields 2,3,4a,5,6,8a-hexahydro-2-hydroxy-2,4a,7-trimethylchroman-4-one (15), the structure of which was confirmed by X-ray analysis.Both (13b) and (15) possess a number of structural features of the trichothecenes and may be of value in their total synthesis.