Transannular Cyclization of (4<i>S</i>,5<i>S</i>)-Germacrone-4,5-epoxide under Basic Conditions to Yield Eudesmane-Type Sesquiterpenes
نویسندگان
چکیده
منابع مشابه
Transannular cyclization of (4S,5S)-germacrone-4,5-epoxide under basic conditions to yield eudesmane-type sesquiterpenes.
Transannular cyclizations of germacrone-4,5-epoxide under acidic and thermal conditions have been reported in our previous study. However, this process gave the different and interesting results under basic conditions. (4S,5S)-Germacrone-4,5-epoxide (1) was treated under basic conditions to yield four products (2-5). Compound 2 was an isomer of 1--(4S,5S,9Z)-4,5-epoxygermacra-7(11),9-dien-8-one...
متن کاملTwo eudesmane sesquiterpenes from Laggera pterodonta.
Two new eudesmane sesquiterpenes, 2alpha-hydroxy pterodontic acid (1) and pterodolide [3alpha-(2-methyl-2,3-epoxy)-butyric-4alpha-acetoxy-8beta-ethoxy eudesma-7(11)-en-8alpha,12-olide (2), along with five known compounds (3-7) were isolated from the aerial parts of Laggera pterodonta. Their structures were elucidated on the basis of spectroscopic methods. The immunosuppressive activity of the i...
متن کاملSynthesis of the macrolactone core of (+)-neopeltolide by transannular cyclization.
The synthesis of the macrolactone core of (+)-neopeltolide has been achieved. The key synthetic strategy involves the highly diastereoselective synthesis of the 2,6-cis-disubstituted tetrahydropyran ring by a transannular cyclization of δ-hydroxy alkene using mercuric trifluoroacetate. Two of the six stereocenters C-5 and C-11 were realized from L-malic acid, while the remaining stereocenters C...
متن کاملA remarkable cyclization of TADDOL-bisthioacetate under oxidative conditions
Attempted oxidation of a TADDOL-derived bisthioacetate resulted in a rather unexpected and remarkable cyclization and deprotection reaction, giving a thiolane-1, 1-dioxide as the main product. Systematic in situ ESI-HRMS studies revealed a bicyclic, highly acid labile key intermediate of this reaction. Supported by force field calculations, the high sensitivity of this intermediate was judged t...
متن کاملAutoxidation of salvinorin A under basic conditions.
[reaction: see text] Treatment of salvinorin A (1a) with KOH in MeOH gave the enedione 3, for which the dienone structure 7 was recently proposed. Also isolated, after methylation, were the secotriesters 4a-c. A mechanism for this unusual series of autoxidations is proposed. Surprisingly, 4a showed weak affinity at the kappa-opioid receptor. Divinatorins A-C (2a-c) showed no affinity at opioid ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Chemical and Pharmaceutical Bulletin
سال: 2014
ISSN: 0009-2363,1347-5223
DOI: 10.1248/cpb.c14-00130