Spirocyclic Ethers Related to Ambrox^®: Synthesis and Structure‐Odor Relationships

Abstract

The seven spirocyclic ethers 4 ± 10, related to the tricyclic odorant Ambrox ¾ (1) and its diastereoisomers 2 and 3, were synthesized. Their odoriferous activity/inactivity was correlated with the steric accessibility of the ether O-atom, calculated by computer-aided molecular modeling. The olfactory properties of the active compounds are discussed.

Labdane-Type Diterpenes, Galangalditerpenes A–C, with Melanogenesis Inhibitory Activity from the Fruit of Alpinia galanga

“…To elucidate the absolute stereostructure, we carried out the conversion of 8 into 2 . As shown in Scheme 1 , the corresponding epoxide 8 , the absolute configuration of which has been reported [ 20 ], was rearranged in the presence of boron trifluoride diethyl ether complex (BF 3 ·Et 2 O) to afford 2 [ 21 ]. Consequently, the absolute stereostructure of 2 was determined to be 5 S , 8 R , 9 S , and 10 R .…”

Chemical Space Exploration of Oxetanes

“…The alcohol 8 was then oxidized to the aldehyde 9 using Dess-Martin periodinane [27] and subsequently converted into the diol 10 and oxetane 11 employing the same reactions mentioned before (Scheme 2). The ketones 1a-c reacted with dimethylsulfonium methylide in a Corey-Chaykovsky epoxidation reaction [19], leading to the epoxide derivatives 2a-c. In the next step, the aldehydes 3a-c were obtained through a Lewis acid catalyzed epoxide rearrangement by a 1,2-hydride shift, namely Meinwald rearrangement [20].…”

“…The solvent was removed under vacuum, and the residue was used without purification for the next step. Adapted from Winter [19].…”

Labdane diterpenes in Curcuma mangga rhizomes inhibit lipid peroxidation, cyclooxygenase enzymes and human tumour cell proliferation

“…-14). Based on the spectral data, compound 7 was identified as 8-methene-1,1,10-trimethyldelcalin (Winter, 2004). -13).…”