Aldehyde aus Acetylen‐carbinolen. I. Cyclohexyliden‐acetaldehyd

The Chemistry of the Alkali Amides.

“…C'. The preparation of acetylenic carbinols Ruzicka, Rupe, and their coworkers (293,294,288,289,290) have found that acetylenic carbinols are easily formed by treat- ing ketones with acetylene in the presence of sodium or sodium amide, the reaction following the type equation…”

Ring cleavage of camphor derivatives: formation of chiral synthons for natural product synthesis

“…However, the results of later investigations (24)(25)(26) indicated that "P-bromocamphor" (mp 78"C), derived from 1 -hydroxycamphene (20) (12), was identical to 10-bromocamphor (21), mp 78"C, prepared by thermolysis of 10-camphorsulfonyl bromide (22) (23) or camphor-10-mercurichloride (23) (26), and this structure assignment is now commonly accepted. It is interesting to realize, however, that a footnote in the paper by Burgess (13) refutes the suggestion by Lipp and Lausberg (25) that "a,P-dibromocamphor" has the 3,lO-dibromocarnphor structure (24), since this is inconsistent with its cleavage to bromo-a-campholenic acid (19). Despite these reservations it is now generally accepted that the early literature describes the conversion of 10-bromocamphor (21) and 3,lO-dibromocamphor (24) to (+)-a-campholenic acid (18) and its bromo derivative (19), respectively.…”

“…It is interesting to realize, however, that a footnote in the paper by Burgess (13) refutes the suggestion by Lipp and Lausberg (25) that "a,P-dibromocamphor" has the 3,lO-dibromocarnphor structure (24), since this is inconsistent with its cleavage to bromo-a-campholenic acid (19). Despite these reservations it is now generally accepted that the early literature describes the conversion of 10-bromocamphor (21) and 3,lO-dibromocamphor (24) to (+)-a-campholenic acid (18) and its bromo derivative (19), respectively. These results, however, are inconsistent with our observations that ring cleavage of 9,lOdibromocamphor (6) provides unsaturated monocyclic compounds (7-9) in which the double bond is exclusively in the 5 i, NaCN/DMSO/heat; ii, DMSO/heat SCHEME 1 i, NaCN /DMS0/80°C or DMS0/80°C SCHEME 2 exocyclic p~s i t i o n .~ As a result of these inconsistencies we treated 10-bromocamphor (21) under various conditions (cf.…”

“…Of particular relevance are reports in the early literature, by Forster (12) and Burgess (13), respectively, which claim that treatment of "P-bromocamphor" (16) (1 2) and "a, P-dibromocamphor" (17) (13) with refluxing KOH/EtOH for 5-8 h produces (+)-acampholenic acid (18) (12) or the corresponding bromo-acid (19) (13). At that time (1900-1924) "P-bromocamphor" and "a,P-dibromocamphor" were assigned structures that, in modem nomenclature, would be named 6-bromocamphor (16) and 3,6-dibromocamphor (17), respectively, and their ring cleavage to (+)-a-campholenic acid (18) and its bromo derivative (19) were consistent with these structural assignments. However, the results of later investigations (24)(25)(26) indicated that "P-bromocamphor" (mp 78"C), derived from 1 -hydroxycamphene (20) (12), was identical to 10-bromocamphor (21), mp 78"C, prepared by thermolysis of 10-camphorsulfonyl bromide (22) (23) or camphor-10-mercurichloride (23) (26), and this structure assignment is now commonly accepted.…”