The usual biochemical process that degrades the chlorophyll occurs only in living tissue. The same is true of certain carbohydrate and protein conversions. If the leaf dies before the green is gone, then the eventual loss of green results in a different pigment degradation product. Typically, leaf that has dried green will tend to remain brittle much longer than color-cured leaf. It also never seems to develop a typical tobacco taste and aroma.
Candela (green) cigar wrapper tastes of chlorophyll, and has a fairly neutral aroma. But when used as filler, it tastes and smells more grassy and harsh. Green-dried leaf will eventually brown, under the right conditions, but it's never the same quality as properly color-cured leaf.
I would suggest letting it hang through the winter, since some of the green will resolve, then kiln it. You may get something smokable. I've found that if the upper surface is browning, even though the underside is still green, it will cure-out, given enough time and suitable conditions.
Bob
