114612-54-3

Upstream product

• 4221-98-1 (R)-5-isopropyl-2-methylcyclohexa-1,3-diene 

Downstream Products

• 1093613-36-5 (1S,4R,5R,6R,7R)-5-methyl-7-(propan-2-yl)-2,3-dioxabicyclo-[2.2.2]octane-5,6-diol 
• 1093613-37-6 (2R,3R,4S,5R)-2,3,4-trihydroxy-2-methyl-5-(propan-2-yl)cyclohexanone 
• 4031-54-3 (3S:4R:6R)-p-menthene-⁽¹⁾-diol-(3.6) 

Relevant academic research and scientific papers

Intrazeolite photo-oxygenation of (R)-(-)-α-phellandrene

Thionin-sensitised intrazeolite photo-oxygenation of (R)-(-)-α-phellandrene affords (1S,5R)-5-(1-methylethyl)-2-methylidene-3-cyclohexen-1-yl hydroperoxide as the major ene product. This can be easily reduced with triphenylphosphine to the natural product trans-yabunikkeol.

Competition of Endoperoxide and Hydroperoxide Formation in the Reaction of Singlet Oxygen with Cyclic, Conjugated Dienes

Rose-bengal-sensitized photooxygenation of (-)-(R)-α-phellandrene (1) in MeOH at room temperature yielded a complex mixture of products, contrary to previous reports describing cis-(3S,6R)-epidioxy-p-menthene (2) and trans-(3R,6S)-epidioxy-p-menthene (3) as the only products.The mixture was separated by prep.HPLC (silica gel, pentane/Et2O 9:1).Besides the known endoperoxides 2 (yield 39 percent) and 3 (26 percent), all those hydroperoxides, which can be deduced from an ene reaction of 1O2 with 1, were isolated, i. e. 4β-p-mentha-2,5-dien-1β-yl hydroperoxide (4) (14 percent), 4β-p-mentha-2,5-dien-1α-yl hydroperoxide (5) (9 percent), (2R,4R)-p-mentha-1(7),5-dien-2-yl hydroperoxide (6) (2.1 percent), (2S,4R)-p-mentha-1(7),5-dien-2-yl hydroperoxide (7) (1.5 percent) and (1R)-p-mentha-3,6-dien-yl hydroperoxide (8; 1.5 percent; Scheme 1).Furthermore, the constant cis/trans ratio for all diastereoisomeric pairs (2/3, 4/5, 6/7) was striking.With the help of the two possible conformers 1a and 1b of the starting material a model of a common first step for endoperoxide as well as for hydroperoxide formation is developed.A photooxygenation at -50 deg C supports this model.The absolute value of the cis/trans ratio changes in the same way for the endoperoxides and the hydroperoxides.

PHOTO-OXIDATION OF α-PHELLANDRENE: THE FORMATION OF CYCLOHEXADIENYL HYDROPEROXIDES AND THEIR REDUCTION TO ARENE 1,4-HYDRATES

Dye-sensitised photo-oxidation of α-phellandrene (3) yields, besides the expected endoperoxides, the cyclohexadienyl hydroperoxides (6) and (7) reduction of these latter gives the unstable arene 1,4-hydrates (9) and (10).