Robert A. Holton, a chemist who created a cheaper and environmentally kinder way to produce cancer drug Taxol, synthesizing its key compound instead of extracting it from harvested yew trees, died May 21 at his home in Tallahassee, Florida. He was 81.

His death was confirmed by his son Paul Holton, who said the cause was emphysema.

In 1993, in his laboratory at Florida State University, where he was a professor, Holton created a method to produce Taxol. He constructed the drug, molecule by molecule, mimicking the plant’s chemistry and eliminating the need to source material from the endangered western yew tree, Taxus brevifolia.

He called the technique, which produced the medication in high amounts, the metal alkoxide process. He licensed his methodology to Bristol Myers Squibb, which became the first pharmaceutical company to manufacture Taxol. Generic versions are sold under the name paclitaxel.

“There was a worldwide race underway to synthesize it,” Dr. Jeff Boyd, chief scientific officer for the Northwell Health Cancer Institute in Manhasset, New York, on Long Island, said in an interview. “Many groups were working on it because what was needed was a cheap and readily obtainable source of the drug. He was the first to achieve total organic synthesis.”

Holton completed the artificially made compound Dec. 9, 1993, beating dozens of competitors. Although scientists at the Scripps Research Institute in La Jolla, California, announced that they had also succeeded in synthesizing the drug, Holton’s team was the first to publish details of its methods in a scientific journal.

Before Holton’s achievement, not only did three yews per patient have to die — because the bark where the anticancer alkaloid was first isolated had to be fully stripped — but the forests where they grew also stood to lose the bulk of these conifers.

Yew trees as a source for cancer treatment first came to scientific attention in the early 1960s. The U.S. government began an extensive search for powerful anticancer compounds lurking in the leaves, twigs, roots and bark of plants nationwide.