Thermoconversion of Caryophyllene- to Farnesene-Type Sesquiterpenes. Short access to the enantiomers of (6RS,7RS)- and (6RS,7SR)-6,7-epoxy-6,7-dihydro-?-farnesenes
作者:Wolfgang K. Giersch、Andr� F. Boschung、Roger L. Snowden、Karl H. Schulte-Elte
DOI:10.1002/hlca.19940770106
日期:1994.2.9
Flash-vacuum thermolysis of the four diastereoisomeric 5,6-epoxy-5,6-dihydro-caryophyllenes 1–4 at 500–550°/0.1–0.7 Torr leads to the hitherto unreported enantiomers of (6RS,7RS)- and (6RS,7SR)-6,7-epoxy-6,7-dihydro-β-farnesenes ((±)-5 and (±)-6, resp.). In particular, (+)-5 is formed in 45% yield (ca. 90% ee) and is, thus, an attractive chiral building block for natural-product synthesis.
在500-550°/ 0.1-0.7 Torr下对4个非对映异构体5,6-环氧-5,6-二氢-石竹烯1-4进行的闪蒸-真空热解反应导致迄今未报道的(6 RS,7 RS)对映体和(6 RS,7 SR)-6,7-环氧-6,7-二氢-β-法呢烯((±)-5和(±)-6,分别)。特别地,(+)- 5以45%的产率(约90%ee)形成,并且因此是用于天然产物合成的有吸引力的手性构件。