ISSN:
0941-1216
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Regio- and Stereospecific Addition of Diazomethane to Gibberellic Acid: A New Effective Pathway to 1α,2α-MethylenegibberellinsA new pathway to 1α,2α-methylenegibberellines via pyrazoline intermediates is reported. In contrast to the addition of diazomethane to the Δ1-double bond of corresponding enones in the case of 1 “Umpolung” of the regioselectivity with cis-addition from the α-side to give pyrazoline ester 4 is observed. Subsequent photolysis of 4 leads to the 1,2-cyclopropyl derivative 6. The structures of the key compounds 4 and 6 are confirmed especially by n.m.r. and X-Ray analysis.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prac.19923340305