A convenient conversion of terminal alkenes into homologous unsaturated and doubly unsaturated esters.

Unsaturated and doubly unsaturated esters have been synthesized in two steps by the application of a radical xanthate transfer process of a simple methylsulfoxide starting material to a range of terminal alkenes. syn-Elimination of the sulfoxide gives α,β-unsaturated esters, which coupled with a xanthate elimination yields α,β,γ,δ-unsaturated esters.

Total synthesis of the Amaryllidaceae alkaloid clivonine.

Two syntheses of the Amaryllidaceae alkaloid clivonine (1) are described. Both employ previously reported 7-arylhydrindane 6 as an intermediate but differ in the method employed for subsequent introduction of what becomes the ring-B lactone carbonyl carbon (C7). The synthesis featuring a Bischler-Napieralski reaction for this transformation constitutes the first asymmetric synthesis of natural (+)-clivonine.

(±)-trans,cis-4-Hydroxy-5,6-di-O-isopropylidenecyclohex-2-ene-1-one: synthesis and facile dimerization to decahydrodibenzofurans.

An efficient synthesis of (±)-trans,cis-4-hydroxy-5,6-di-O-isopropylidenecyclohex-2-ene-1-one (3) has been developed from acetonide-protected meso-1,2-dihydrocatechol derivative 1 via photooxygenation, then Kornblum-DeLaMare rearrangement. The product is unstable unless its 4-hydroxy group is protected, as it undergoes facile dimerization in solution to a 1:1 mixture of diastereoisomeric decahydrodibenzofurans 8 and 9. A new synthesis of the dihydrocatechol 1 from 1,3-cyclohexadiene has also been developed.

Total synthesis of the lycorenine-type amaryllidaceae alkaloid (+/-)-clivonine via a biomimetic ring-switch from a lycorine-type progenitor.

A fully diastereoselective total synthesis of the lycorenine-type Amaryllidaceae alkaloid (+/-)-clivonine (19) is reported via a route that employs for the first time a biomimetic ring-switch from a lycorine-type progenitor, thereby corroborating experimentally the biogenetic hypothesis first expounded for these compounds by Barton in 1960.