Trifluoromethanesulfonic acid, an efficient catalyst for the hetero Diels-Alder reaction and an improved synthesis of mefrosol

Tetrahedron Letters

Volumn 38, Issue 14, 1997, Pages 2569-2572

  Aggarwal, Varinder K ^a   Vennall, Graham P ^a   Davey, Paul N ^b   Newman, Chris ^b  

^a UNIVERSITY OF SHEFFIELD   (United Kingdom)

^b Givaudan SA   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

ALDEHYDE; ALKADIENE; FRAGRANCE; HETEROCYCLIC COMPOUND; MEFROSOL; UNCLASSIFIED DRUG;

ARTICLE; CATALYSIS; CHEMICAL REACTION; DRUG SYNTHESIS;

EID: 0030904917     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)00403-6     Document Type: Article

References (13)

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10. Broekhof N.L.J.M., Hofma J.J., Renes H., Sell C.S. Perfumer & Flavorist. 17:1992;11. and references cited therein.
11. 3) and dried over magnesium sulfate. Purification by flash chromatography (silica gel, 2% EtOAc/Petroleum (b.p. 40-60)) gave the pure pyran (883 mg, 5.07 mmol, 72 % based on recovered aldehyde) as a colourless oil, and benzaldehyde (320 mg, 3.01 mmol).
12. Increasing the amount of aldehyde in the reaction to three equivalents resulted in increased yields (60-85%) and diastereoselectivities (>90:10) of the Prins products.
13. Equilibration of the cis/trans carbocations can occur either by formation of oxetane intermediates or by reversion to starting materials.