791104-81-9

Upstream product

• 791104-74-0 1-phenyl-2-((1R,4R)-4,5,5-trimethylcyclopent-2-en-1-yl)ethan-1-one 
• 10293-06-8 (1R)-3-endo-bromocamphor 
• 33171-48-1 (1S,4R,6S)-6-bromo-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one 
• 104832-00-0 (1S,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-5-en-2-one 
• 791104-70-6 (1S,2R,4R)-1,7,7-trimethyl-2-phenylbicyclo[2.2.1]hept-5-en-2-ol 
• 464-49-3 (1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-one 
• 31503-04-5 Phenylborneol 

Relevant academic research and scientific papers

Thermal isomerization of isoborneols and dehydroisoborneols to new chiral building blocks in terpenoid synthesis

The substituted isoborneols 1a-1g and 5,6-dehydroisoborneols 6a-6c, readily prepared in excellent yields from (+)-camphor and (+)-5,6-dehydrocamphor (2) by aryl, vinyl, or alkyl Grignard addition in the presence of stoichiometric amounts of CeCl3, were thermally isomerized in a flow reactor system under DGPTI (dynamic gas-phase thermo-isomerization) conditions at temperatures between 480 and 630° to give the enantiomerically pure monocyclic carbonyl compounds 7a-7d, 19a,b, 23, and 24. In all cases, product formation proceeded highly regio- as well as stereoselectively. The absolute configurations of the new stereogenic centers were determined by 1H-NOE measurements. DGPTI of the aryl substrates 1a-1d is proposed to effect initial cleavage of the weakest single bond in the molecule under formation of a diradical intermediate state followed by intramolecular H-abstraction to afford the acetophenone derivatives 7a-7d. This reaction path was further supported by a 2H-labeling study showing the OH group to be the exclusive H-source. In contrast, DGPTI of the vinyl substrates 1e and 6b allowed concerted retro-ene and oxy-Cope rearrangements. In the case of 5,6-dehydro-2-phenylisoborneol (6a), concomitant diradical and retro-Diels-Alder reaction pathways could be observed. In addition, a new route to (+)-rrans-a-campholanic acid (9) and (+)-trans-a-dihydrocampholytic acid (14) is presented by regioselective Baeyer-Villiger oxidation and subsequent hydrolysis of 7c and 7d, respectively.

Stereo- and regioselectivity in dynamic gas-phase thermoisomerization (DGPTI): Novel route to α-campholanic acid and derivatives

(Matrix presented) Dynamic gas-phase thermoisomerization (DGPTI) of (-)-2-phenylisoborneols effects stereo- and regioselective ring opening under formation of (+)-trans-α-campholanic acid derivatives. Similarly, (-)-α-2-phenylfenchol underwent under DGPTI conditions ring opening to (-)-fencholic acid derivatives. In both cases, DGPTI led to cleavage of the weakest bond in the isomeric bicyclic structures. A reaction mechanism involving a diradical intermediate is supported by a deuterium labeling study.