At a glance
Firm: Alchemy Properties Founder & principal: Kenneth S. Horn (President); Joel Breitkopf (Principal) Founded: 1990 (New York City) Headquarters: New York, NY Focus: Boutique luxury condominium development — both ground-up construction and high-design conversions, concentrated in Manhattan Frequent design partners: FXFowle / FXCollaborative, COOKFOX, Thierry Despont, Robert A.M. Stern Architects Portfolio scale: Reported at more than 3 million square feet of luxury condominium residences and 30-plus buildings developed or converted over three decades Signature project: The Woolworth Tower Residences — the landmark conversion of the top floors of the Woolworth Building into condominiums Signature reputation: A careful, design-led boutique developer with a clean building-quality record — whose principal challenge has been market execution at the ultra-luxury top end Source: The Roebling Team at Compass — verified against public records, court filings, and published reporting. July 2026.
Who Alchemy Properties is
Alchemy Properties is the firm of Kenneth S. Horn, who co-founded the company in 1990 and has spent more than three decades building one of Manhattan's most respected boutique luxury-condominium platforms. Horn is a lawyer by training — a member of the New York State Bar, a former NYU real-estate professor, and a lecturer at Yale, Wharton, and Penn — and that temperament shows in the firm's approach: measured, design-forward, and unusually willing to hold on price rather than discount into a soft market. His longtime partner Joel Breitkopf, a principal since 1993, works across acquisition, finance, design, construction, and marketing.
For a buyer, the relevant point is consistency of intent. Alchemy is a boutique developer by design — buildings measured in dozens of residences, not hundreds — and it works in two modes: ground-up construction of small, architect-led condominiums, and careful conversions, of which the top-floor transformation of the Woolworth Building is the landmark example. This is a developer that builds a specific kind of building and has done so, quietly and well, across multiple cycles.
What they build
Alchemy's signature is the small, design-led Manhattan condominium — most often in the boutique-luxury band, with a recognizable roster of architects. The firm has worked repeatedly with FXFowle / FXCollaborative (35XV, the Oculus, Hudson Hill, and the NoMad building at 846 Sixth Avenue), with COOKFOX (378 West End Avenue), with Thierry Despont (the Woolworth Tower Residences), and with Robert A.M. Stern Architects (250 West 81st Street, elsewhere in the book).
The firm is also known for ingenious site work — the air-rights deal that unlocked 35XV (built over Xavier High School) was recognized by the industry as one of the more creative land plays of its era — and for the patience to assemble complex sites from many owners, as at the NoMad project. The product is boutique, well-finished, and pitched at the upper-mid to luxury tier rather than the trophy extreme, with the Woolworth as the singular ultra-luxury exception.
Buildings by Alchemy Properties
Alchemy projects already profiled on this site:
- 121 West 19th Street (The Lion's Head) — a 67-unit conversion of a 1903 Chelsea building
- 35 West 15th Street (35XV) — an FXFowle ground-up condominium built over Xavier High School on a widely praised air-rights deal
- 50 West 15th Street (The Oculus) — a boutique FXFowle condominium
- 378 West End Avenue — a COOKFOX-designed ground-up Upper West Side condominium
- 462 West 58th Street (Hudson Hill) — a boutique FXFowle condominium
- 800 Tenth Avenue (Griffon Court) — a 95-residence condominium
- 846 Avenue of the Americas — the FXFowle-designed NoMad condominium, assembled from a large group of adjacent parcels
Alchemy's defining project — not yet profiled here — is the Woolworth Tower Residences at 2 Park Place / 233 Broadway: the conversion of the top thirty floors of Cass Gilbert's landmark Woolworth Building into 32 condominiums, with interiors by Thierry Despont and a five-story "Pinnacle" penthouse. It remains one of the most ambitious landmark-conversion projects in the city.
Track record and market performance
Across its boutique book — the Oculus, the Lion's Head, 35XV, Hudson Hill, and the NoMad building — Alchemy's condominiums are well-regarded and have absorbed normally, positioned in the upper-mid to luxury tier where the firm's careful product and design pedigree carry.
The revealing chapter is the Woolworth Tower Residences, which is both the firm's signature achievement and its clearest market cautionary tale. Alchemy bought the building's top thirty floors for $68 million in 2012 and launched condominium sales in 2014, straight into what became a prolonged ultra-luxury slowdown. True to the firm's character, Alchemy declined to discount aggressively — and paid for that discipline with time: the building took the better part of a decade to sell out, reaching a full sellout in 2023. The signature data point is the "Pinnacle" penthouse, listed at $110 million in 2017 (then the highest ask ever for a downtown apartment) and ultimately sold, as a raw white-box, for roughly $30 million in 2023 — a fraction of the original ask, and a stark illustration of how thin the very top of the ultra-luxury market can be. For a buyer, the lesson is about the segment, not the builder: the Woolworth's slow absorption was a market-and-pricing story at the extreme high end, not a quality problem.
Reputation and what a buyer should know
Alchemy is, on the available evidence, a clean-record boutique developer — and the honest read is to say so plainly, while distinguishing the one real dispute in the file.
On build quality. We found no verified construction-defect litigation — no facade, water-intrusion, mechanical, or structural defect suit, and no condo-board defect action — against any completed Alchemy condominium in the public reporting and records reviewed. Alchemy's reputation as a careful, quality-focused boutique developer appears supported by the record. As always, this is a negative finding based on public sources rather than a formal per-building court-docket certification, so standard diligence still applies — but no defect red flag surfaced. (A widely searched Manhattan skyscraper-defect case — the one involving thousands of alleged facade cracks — belongs to 432 Park Avenue, a different building by different developers, and has nothing to do with Alchemy.)
On commercial disputes — real, but not a building-quality issue. The one documented dispute in the file is commercial: at the Woolworth conversion, a contractor (CNY Construction) filed a mechanic's lien and, in a 2020 Manhattan Supreme Court complaint, sued Alchemy over allegedly unpaid fees of roughly $1 million. Per public records and published reporting, that is a payment/fee dispute between developer and trade — not a construction defect — and its resolution was not established in the record reviewed. A buyer's counsel should, as a matter of routine, confirm there are no open mechanic's liens at closing, but this is not a quality issue.
One important disambiguation. Reporting has referenced a large loan (roughly $222 million) in distress at the Woolworth Building — but that debt is secured by the building's office space, which is owned by other parties (the Witkoff Group and Cammeby's), not by Alchemy. Alchemy owns only the separately titled residential condominium tower. That office-loan distress should not be attributed to Alchemy or read against the residential condominium.
Frivolous and NIMBY complaints are not treated as issues here. For a buyer, the practical rule is straightforward: apply standard resale or new-development diligence — offering plan, lien and title status, warranty, and reserves — with no defect red flag specific to an Alchemy building in the record we reviewed.
The Roebling Team on Alchemy buildings
We publish developer profiles because a buyer choosing a new-construction or recently-converted condominium is, in part, betting on the developer — its quality, its staying power, and its record when things go wrong. The Roebling Team at Compass tracks the sponsors behind Manhattan's luxury inventory building by building, and we bring that context to every new-development transaction: what the developer has built, how those buildings have held value, and what to verify before you sign.
If you're evaluating an Alchemy building — or weighing it against another sponsor's product — a 30-minute consultation is the right starting point.
Corey Cohen, Principal · The Roebling Team at Compass 646.939.7375 · c.cohen@compass.com
This developer profile reflects publicly available information — including NYC public records, court filings, and published reporting — and The Roebling Team's transaction experience. It is provided for research purposes and is not legal advice; nothing here alleges wrongdoing or building defects beyond what the cited public record supports. Commercial and financing matters described above are distinct from building-quality matters and are not construction-defect allegations. The Roebling Team at Compass does not represent Alchemy Properties. © 2026 The Roebling Team at Compass.