BCE Synthesis from MCPD via One-Step Metal Alkoxide Reaction
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Solution Overview
Problem
Existing methods for converting 3-methyl-1,5-cyclopentadecanedione (MCPD) to 14-methyl-16-oxabicyclo[10.3.1]hexadec-12-ene (BCE) are inefficient, require multiple steps, use expensive catalysts, and generate unwanted byproducts, making them unsuitable for commercial scale production.
Innovation Solution
A one-step process involving the reaction of MCPD with a metal or metalloid alkoxide in an inert solvent, followed by treatment with an aqueous mineral acid, to directly convert MCPD to BCE with high selectivity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If MCPD is converted to BCE via two-step process through DIOL using Raney copper catalyst, then BCE is produced, but the process requires expensive catalyst and prolonged reaction time generating hydrogen gas that reduces BCE to saturated byproduct
Solution Approach 1:
The patent segments the two-step process (MCPD→DIOL→BCE) into a direct one-step transformation (MCPD→BCE) using metal alkoxide catalysts. This eliminates the intermediate DIOL isolation step and the subsequent dehydrogenation step, reducing total reaction time from multiple hours to a single reaction step while avoiding hydrogen gas generation that causes byproduct formation.
Solution Approach 2:
The patent changes the catalyst system from Raney copper (requiring high temperature 160-165°C and prolonged time) to metal alkoxides (aluminum, boron, magnesium, zinc, calcium, or lanthanide alkoxides) that operate under milder conditions. This parameter change in catalyst chemistry enables faster reaction rates and eliminates the need for extended reaction times that lead to BCE reduction by generated hydrogen.
2Quantity of substance
If Raney copper catalyst is used for dehydrogenation-dehydration of DIOL to BCE, then BCE is formed, but expensive catalyst and prolonged reaction time are required
Solution Approach 1:
The patent replaces the expensive Raney copper catalyst with cheaper metal alkoxide catalysts (aluminum alkoxides, boron alkoxides, magnesium alkoxides, zinc alkoxides, calcium alkoxides, or lanthanide alkoxides). These alternative catalysts achieve the same transformation at lower cost and can be used in catalytic amounts without requiring the expensive preparation and handling infrastructure needed for Raney copper.
Solution Approach 2:
The patent changes the catalyst type from Raney copper to metal alkoxides, fundamentally altering the reaction mechanism from dehydrogenation-dehydration to a direct cyclization. This parameter change eliminates the need for costly catalyst preparation, reduces catalyst handling complexity, and lowers overall process cost while maintaining high BCE yields.
3Quantity of substance
If ozonolysis is applied to prepare DIOL from 14-methylbicyclo[10.3.0][1(12)]pentadecene, then DIOL is obtained, but hazardous conditions and expensive molybdenum-doped Raney nickel catalyst are required
Solution Approach 1:
The patent extracts and eliminates the hazardous ozonolysis step from the synthesis pathway. Instead of converting 14-methylbicyclo[10.3.0][1(12)]pentadecene to DIOL through ozonolysis followed by hydrogenolysis, the invention uses a direct metal alkoxide-catalyzed transformation of MCPD to BCE, completely removing the explosive intermediate (14-methyl-16,17,18-trioxatricyclo-[10.3.2.11,12]octadecane) and the need for molybdenum-doped Raney nickel catalyst.
Solution Approach 2:
The patent converts the potentially harmful ozonolysis pathway into a benign direct cyclization reaction. By using metal alkoxides as catalysts, the process transforms what would be a hazardous multi-step sequence involving explosive intermediates into a safe, one-step reaction that proceeds under mild conditions without generating harmful byproducts or requiring expensive specialized catalysts.
4Manufacturing precision
If 1-hexadecanol is added as solvent and BCE is distilled off as formed, then formation of saturated BCE byproduct is minimized, but process complexity increases due to high boiling point solvent recycling
Solution Approach 1:
The patent extracts and removes the need for high-boiling-point 1-hexadecanol solvent from the reaction system. By using metal alkoxide catalysts in alternative solvents or under solvent-free conditions, the process eliminates the complex solvent recycling infrastructure required for 1-hexadecanol, simplifying the overall process while maintaining BCE purity through the inherent selectivity of the metal alkoxide-catalyzed reaction.
Solution Approach 2:
The patent changes the solvent system from high-boiling-point 1-hexadecanol to more volatile or easily removable solvents compatible with metal alkoxide catalysis. This parameter change in solvent selection eliminates the need for complex high-temperature recycling equipment while maintaining reaction efficiency and product purity through the selective action of metal alkoxide catalysts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process achieves a high yield of BCE with minimal byproducts, using readily available and cost-effective reagents, suitable for commercial-scale production.
Implementation Method 1
reacting 3-methyl-1,5-cyclopentadecanedione (MCPD) with a C1-C4 alkoxide of a metal or metalloid selected from the group consisting of sodium, magnesium, aluminum, boron, tin, zirconium and lanthanides
Implementation Method 2
treating the reaction mixture with an aqueous mineral acid
Implementation Method 3
treating the reaction mixture with an aqueous mineral acid. The process can further comprise isolating the product, BCE, through extraction and/or distillation
Data Source
AI summary
Disclosed is a scalable process for preparation of 14-methyl-16-oxabicyclo[10.3.1]hexadec-12-ene (BCE), a key intermediate for manufacture of fragrance ingredient 3-methylcyclopentadecenone (MUSCENONE®) and analogs through reaction of 3-Methyl-1,5-cyclopentadecanedione (MCPD) and analogs with a metal or metalloid alkoxide in high yield and purity.