Theoretical calculation of effects of steric hindrance on rates of

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J. Org. Chem. 1987,52, 2074-2082

alyzed by LSC. After the appropriate fractions were collected, LSC showed 1.1 fiCi (31%) incorporation. The exo and endo pyrophosphates ([aH]-13-OPPand [%]-14-OPP) were incubated with kaurene synthetase, using the same procedure. After the column chromatographic separation, only negligible radioactivity (